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Stefanos Tsitsipas registered a historic run of upsets at the Rogers Cup in Toronto.

The Five Biggest ATP World Tour Upsets Of 2018

ATP World Tour Season In Review: Biggest ATP Upsets

Continuing our Season In Review series, ATPWorldTour.com revisits the Top 5 ATP World Tour upsets of 2018. On Tuesday, return to learn about the Top 5 Grand Slam upsets.

(5) Marius Copil d. Marin Cilic & Alexander Zverev – Basel 2R & SF
For Marius Copil, it was a surreal experience under the bright lights of the St. Jakobshalle in Basel. Competing in his last tournament of the year, the Romanian put a giant bow on his campaign. Not only did Copil reach his biggest final, but he claimed the first Top 10 scalps of his career along the way.  

Just three days after celebrating his 28th birthday, he entered the ATP World Tour 500 event as a qualifier, in search of a strong finish to the season. With one win in his past six matches, Copil was far from the favourite to come through his half of the draw, but his big game translated to the speedy indoor hard courts in the Swiss city. 

All it takes is one tournament to change a player's fortunes and this was that week. Copil did not drop a set in breezing through qualifying and reaching the second round of the main draw, where he would stun World No. 6 Marin Cilic 7-5, 7-6(2).

The Romanian entered the week at the Swiss Indoors Basel with an 0-6 record against Top 10 opponents in his career. And he would not settle for just one. After dismissing Taylor Fritz in the quarter-finals, he battled past World No. 5 Alexander Zverev to reach the championship. Considering that the German would go on to lift the trophy at the Nitto ATP Finals, the 6-3, 6-7(6), 6-4 victory was a massive moment for Copil. 

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Copil stunned Zverev in two hours and 31 minutes, becoming the lowest-ranked finalist in Basel since Patrick McEnroe in 1994. He frustrated the German throughout the match with his aggressive tactics, frequently serve and volleying as well as mixing up his shot selection. The World No. 93 would be rewarded in the ATP Rankings, soaring to a career-high No. 60 and capping a breakthrough season that saw him reach his first ATP World Tour finals. Also the runner-up in Sofia in February, his magical run in Basel would come to an end at the hands of nine-time champion Roger Federer.

"I would love for it to be the beginning of my career at this level," Copil added. "After this amazing week, I've just gained a lot of confidence in myself and I saw that I can play a much higher level of tennis and I could keep it up."

(4) Lamine Ouahab d. Philipp Kohlschreiber 2-6, 6-0, 7-6(3) – Marrakech 1R
They say that home is where the heart is. This couldn't be closer to the truth for Lamine Ouahab. Spurred on by the Moroccan faithful, the 33-year-old sprung one of the biggest upsets of the year in his home ATP World Tour event of Marrakech in April.

Ouahab entered the week at the Grand Prix Hassan II at No. 617 in the ATP Rankings and he would leave with a stunning victory over 34th-ranked Philipp Kohlschreiber. It goes down as the fifth-biggest upset of the year (by ranking) at the tour-level, behind only Pablo Andujar's win over Gerald Melzer in Rio de Janeiro and a resurgent Andy Murray's trio of Top 100 triumphs at the Citi Open.

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This is certainly not the first time Ouahab has conjured moments of magic on home soil. In seven appearances at the ATP World Tour 250 event, he owns four wins against Top 100 players, including a standout victory over then-No. 24 Guillermo Garcia-Lopez in 2015.

Biggest ATP World Tour Upsets Of 2018 (by ATP Ranking)

Winner Opponent Tournament
No. 1821 Pablo Andujar No. 110 Gerald Melzer Rio de Janeiro
No. 832 Andy Murray No. 18 Kyle Edmund
No. 832 Andy Murray No. 80 Mackenzie McDonald Washington
No. 832 Andy Murray No. 93 Marius Copil Washington
No. 617 Lamine Ouahab No. 34 Philipp Kohlschreiber Marrakech
No. 654 James Duckworth  No. 105 Jason Kubler  Washington 
No. 426 Jurgen Melzer  No. 22 Milos Raonic  Vienna 

In this year's first round, Ouahab provided the shock of the tournament in defeating Kohlschreiber, rallying from a set down in his first ATP World Tour match in two years. The German was coming off an appearance in the final in 2017 and he would fall after one hour and 34 minutes.

"I was quite tense at the beginning," admitted Ouahab. "This is my only chance to play an ATP World Tour-level event and it means a lot to me with a lot at stake."

(3) Borna Coric d. Roger Federer 7-6(6), 3-6, 6-2 – Halle final
On June 24, Roger Federer attempted to achieve something for the first time in his storied career: Win 10 titles at a single tournament. His dominance of the Gerry Weber Open is nothing short of awe-inspiring. 

Entering this year's edition, Federer had prevailed in nine of 11 finals on the lawns of Halle. Only former World No. 1 Lleyton Hewitt (2010) and former No. 2 Tommy Haas (2012) had gotten the better of him in championship clashes. But that would all change as the 37-year-old entered the Gerry Weber Stadion, bidding for a 10th trophy at the ATP World Tour 500 event.

Enter Borna Coric. If 2018 was the Croatian's big breakthrough on the ATP World Tour, his victory over then-World No. 1 Federer in the Halle final was his breakout moment. Coric opened the tournament with just two wins in nine tour-level matches on grass, but he would streak to the title with the loss of just one set.

"[I am] just really surprised... I had not even dreamed of this," said Coric.

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Coric, who also beat second seed Alexander Zverev in the first round, snapped Federer's 20-match win streak on grass after two hours and six minutes. After splitting sets, the 22-year-old would take charge midway through the decider. He stepped up his aggression to secure a 4-2 lead before breaking once more, two games later, to clinch the biggest title of his career.

"It is the most unbelievable feeling, [to beat Federer],"  Coric added. "I looked up to him when I was younger, watching his matches back at home with my mum, my dad and my sister. Just playing him here today was a very special moment and beating him just makes it even bigger for me."

Halle was just the start for Coric, as the Croatian would go on to reach his first ATP World Tour Masters 1000 final later in the season in Shanghai. His opponent in the semis? Federer once again. Coric carried the momentum from his victory in Halle to the Rolex Shanghai Masters, stunning the reigning champion 6-4, 6-4. 

Coric would go on to finish his 2018 campaign at a career-high No. 12 in the ATP Rankings, appearing at the Nitto ATP Finals as an alternate.

(2) Thanasi Kokkinakis d. Roger Federer 3-6, 6-3, 7-6(4) – Miami 2R
Thanasi Kokkinakis' 2018 campaign was a microcosm of his career thus far. The highest of highs have thrust him into the spotlight as one of the ATP's brightest young talents, while chronic injuries have frequently derailed his aspirations.

As the season got underway, groin and pectoral strains were followed by a rolled ankle at an ATP Challenger Tour event in Mexico. Competing in just his fifth main draw in seven months, the 22-year-old Aussie was sitting at No. 175 in the ATP Rankings as he entered the Miami Open presented by Itau. And he would provide one of the biggest shocks of the season on one of the ATP World Tour's biggest stages.

After marching through qualifying and blasting Calvin Hemery 6-1, 6-2 in the first round, Kokkinakis stunned Roger Federer 3-6, 6-3, 7-6(4) in a marathon two hours and 21 minutes. He stormed back from a set down to defeat the World No. 1, using his crisp movement and flowing forehand to shock the Miami faithful on a packed Stadium court.

Lowest-Ranked Players To Upset A World No. 1 (since 1984)

ATP Ranking Upset Year Tournament
No. 238 Daniel Nestor d. Stefan Edberg 1992  Davis Cup
No. 205 Karim Alami d. Pete Sampras 1994  Doha
No. 193
Andrei Olhovskiy d. Jim Courier 1992  Wimbledon
No. 178 Francisco Clavet d. Lleyton Hewitt 2003  Miami
No. 175 Thanasi Kokkinakis d. Roger Federer 2018  Miami
No. 161 Sandon Stolle d. Thomas Muster 1996  Dubai

Kokkinakis secured his second Top 10 victory and first over a Top 5 opponent, dethroning the defending champion and handing Federer his earliest defeat in Miami since 2000. But perhaps the most jaw-dropping stat is this: Kokkinakis became the fifth-lowest ranked player to upset a World No. 1 (since 1984) and the lowest since No. 178 Francisco Clavet stunned Lleyton Hewitt in Miami 2003.

Both players were trending in opposite directions as the tournament got underway. Federer, who was competing in his second event since returning to the summit of the ATP Rankings, was carrying great momentum. The Swiss put together a career-best 17-0 start to the season, and his only loss came in the BNP Paribas Open final, where he held three championship points before succumbing to Juan Martin del Potro.

That good form showed, as the trademark Federer swagger was on full display in the early stages. A sublime behind-the-back volley saw him surge to a one-set lead. 

But proceedings suddenly swung to Kokkinakis' side of the court, as Federer's first-serve percentage plummeted and the Adelaide native refused to falter with the match in the balance. In the third set, he would survive a 5-6 0/30 deficit and battled to victory in the deciding tie-break.

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"This is nuts," said Kokkinakis. "It's an unreal week for me. I've trained with [Federer] a bunch of times and he's a great role model for the sport, but I took what I learned and played my game and executed. I didn't put a lot of scoreboard pressure on him, but I was playing on my own terms today.”

Kokkinakis would fall to Fernando Verdasco in the next round, but his story of 2018 would not end there. In August, the Aussie clinched his first ATP Challenger Tour title in three years in Aptos, California, and he would close his campaign with another trophy in Las Vegas in October, rising to year-end No. 152 in the ATP Rankings.

(1) Stefanos Tsitsipas d. four straight Top 10 players  Toronto
It's only fitting that Stefanos Tsitsipas' historic run to the Rogers Cup final would register at No. 1 on our list. Tsitsipas earned Most Improved Player of the Year honours in the 2018 ATP Awards presented by Moët & Chandon, and it was in Toronto where he made his biggest stride.

Tsitsipas entered the ATP World Tour Masters 1000 event with three wins over Top 10 opposition and he would more than double that in just one week. Victories over World No. 8 Dominic Thiem, No. 10 Novak Djokovic, No. 3 Alexander Zverev and No. 6 Kevin Anderson sealed his place in the record books. The 20-year-old is the youngest player to beat four Top 10 opponents at a single tournament since the ATP World Tour was established in 1990. His reward? A berth in his first Masters 1000 championship against Rafael Nadal.

"Playing in a Masters 1000 final is the best thing that can happen on your birthday," said Tsitsipas. "I cannot believe it... I couldn't achieve anything better in one tournament, beating all those high-ranked players, playing amazing tennis," Tsitsipas said. "I'm pretty sure the crowd didn't expect that. I personally didn't expect that."

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After breezing past Damir Dzumhur in the first round, Tsitsipas kicked off his Top 10 assault with a 6-3, 7-6(6) win over Dominic Thiem. It was his fifth FedEx ATP Head2Head meeting with the Austrian this year, having also prevailed over his new rival en route to the Barcelona final.

Considering how Djokovic finished the season, Tsitsipas' next win was arguably his most impressive. He overcame the eventual year-end No. 1 by a 6-3, 6-7(5), 6-3 score, handing Djokovic his first of just three post-Wimbledon defeats. The Athens native faced two break points and saved them both, emerging victorious in two hours and 18 minutes.

In the quarter-finals, Tsitsipas would stun defending champion Zverev for his first Top 5 win. He produced a stunning comeback, saving two match points to triumph 3-6, 7-6(11), 6-4. The Greek hit 28 winners to come from 3-6, 2-5 down and avenge a semi-final defeat to the German a week prior in Washington.

The final piece of the puzzle came a day later in the semi-finals, when Tsitsipas rallied from a set down once again. He denied a match point to stun Anderson 6-7(4), 6-4, 7-6(7), securing his spot in the title match. 

It was the shining moment of Tsitsipas' season and the catalyst to even bigger things. The #NextGenATP star would cap his campaign at No. 15 in the year-end ATP Rankings, clinching his maiden ATP World Tour trophy in Stockholm and capturing the title at the Next Gen ATP Finals in Milan.