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Roger Federer, Dominic Thiem, Stefanos Tsitsipas and Felix Auger-Aliassime have been among standout performers in the first quarter of 2019

Top Seven Stories Of 2019 So Far

ATPTour.com recaps the storylines from the first quarter of the season

The season is only three months old, but there's already a plethora of storylines to track. Here are the top seven stories of 2019 so far:

1. Federer Starts With A Bang (Again)
Roger Federer is proving age is just a number in 2019 after yet another impressive start to the season. So far in 2019, the Swiss superstar has become the second player in the Open Era to claim 100 career titles and also captured his 28th ATP Masters 1000 crown.

The 37-year-old has won 15 of his past 16 matches including a seventh trophy at the Dubai Duty Free Tennis Championships (d. Tsitsipas), which saw him follow in the footsteps of American Jimmy Connors (109 titles), a runner-up finish at the BNP Paribas Open in Indian Wells (l. to Thiem) and a fourth Miami Open presented by Itau title (d. Isner). Read & Watch Miami Final Highlights

Federer, with an 18-2 record this year, got off to a 17-2 start after three minutes in 2018, with the Australian Open and ABN AMRO World Tennis Tournament crowns, which helped him rise to No. 1 in the ATP Rankings, and went 19-1 in 2017, including trophies in Melbourne, Indian Wells and Miami.

Having entered Indian Wells with 680 points in the ATP Race To London, he now leads the year-to-date standings with 2,280 points — 55 points ahead of second-placed Serbian Novak Djokovic (2,225). After three months of the season, the Swiss leads the battle for a place at the Nitto ATP Finals, to be held at The O2 in London from 10-17 November.

2. Tsitsipas Backs Up Next Gen ATP Finals Success
Stefanos Tsitsipas continues his surge as one of the sport’s youngest and most charismatic stars. Four months on from capturing the 2018 Next Gen ATP Finals title, the 20-year-old has become the first Greek to break into the Top 10 of the ATP Rankings — and this week moved up to a career-high No. 8. Read Latest ATP Rankings Movers Of The Week

In starting 2019 at No. 15, Tsitsipas recorded the biggest win of his career over Roger Federer en route to the Australian Open semi-finals (l. to Nadal) — the youngest Grand Slam semi-finalist since 20-year-old Djokovic at the 2007 US Open — and the following month he clinched his second ATP Tour title at the Open 13 Provence in Marseille (d. Kukushkin).

The YouTube vlogger, with 140,000 followers, also advanced to the Dubai final (l. to Federer), dropping to 2-3 in title matches, but at No. 4 in the ATP Race To London (145 points behind third-placed Rafael Nadal), Tsitsipas is well-placed for a first qualification to the eight-man season finale in November.

3. Felix’s Meteoric Rise
Ever since Felix Auger-Aliassime became the youngest player to win a main draw match on the ATP Challenger Tour at the age of 14, the Canadian has been on the global radar. Over the past three months, the 18-year-old has soared from No. 108 in the ATP Rankings to his current career-high of No. 33.

His confidence has grown as a result of reaching his first ATP Tour final at the Rio Open presented by Claro (l. to Djere) on 24 February. He went on to record his first Top 10 victory against then No. 10-ranked Tsitsipas in the BNP Paribas Open second round, then qualified for Miami and became the ATP Masters 1000 tournament’s youngest semi-finalist for 35 years (l. to Isner).

He’s in second position, behind Tsitsipas, in the ATP Race To Milan for a place at the 21-and-under Next Gen ATP Finals in Milan and, one of three Canadians — also Milos Raonic and Denis Shapovalov — in the Top 14 of the ATP Race To London. After Shapovalov also reached the Miami semi-finals, the Canadians are pushing each other to new heights.

Read Feature - Felix's Philosophy: 'I'm Not Scared Of Losing' 

4. Thiem Expands His Horizons
Dominic Thiem has forged a reputation in recent years as a clay-court ironman, befitting the reputation of his Austrian predecessor Thomas Muster. But after having gotten off a 3-4 start to the year — including appearances at two clay-court tournaments — heading into Indian Wells, the 25-year-old needed a confidence boost.

In the space of 10 days, and with former World No. 9 Nicolas Massu as a part of his team alongside long-time coach Gunter Bresnik, Thiem won six straight matches — including three-set victories over Raonic and No. 4-ranked Federer — for the biggest title of his career, his first ATP Masters 1000 crown.

Read Feature: Massu On Thiem: "Ask Dom To Do Something And He'll Do It – Just Better"

World No. 5 Thiem now has 1,990 ATP Rankings points to defend on the upcoming European clay-court swing, which includes 1,200 points from a 2018 runner-up finish at Roland Garros.

5. Silverware Gets Spread Out
When Federer defeated Isner in the final of the Miami Open presented by Itau on Sunday, he ended a record-breaking ATP Tour streak of 19 tournaments in a row that had until then produced 19 different singles winners.

He was the season’s first repeat winner in the most competitive season to date in ATP Tour history. Never before had it taken so long to produce a multiple champion. The remarkable diversity in winners, with players aged from 20 to 37, is a dramatic indication of the continuing rapidly growing depth in the men’s professional tennis.

6. Djokovic Extends ATP Rankings Lead, Now For Clay Bid
Djokovic started the year in imperial form with a record seventh Australian Open crown, but for a second straight year left March’s two Masters 1000 tournaments with little to show. After a BNP Paribas Open third-round exit (l. to Kohlschreiber) and a Last 16 loss in Miami (l. to Bautista Agut), fans are wondering what to expect for the clay-court swing.

The Serbian has a 2,345-point lead over second-placed Nadal (2,345), the player he beat in the Melbourne final, in the ATP Rankings. Djokovic started 2019 with 9,135 points and now has 11,070 points, in comparison to Nadal’s current tally of 8,725 points.

View Latest ATP Rankings

Nadal, who has not competed since 15 March, is scheduled to return at the Rolex Monte-Carlo Masters that begins on 14 April. The Spaniard has 4,680 ATP Ranking points to defend after triumphing in Monte-Carlo, Barcelona, Rome and Paris last year, while Djokovic, who has finished as the year-end No. 1 in 2011-12, 2013-14 and 2018, has a total of 855 points to defend on red dirt.

7. Motivated Monfils On Comeback Trail
One of the sport’s greatest sights is watching the athletic and flexible Gael Monfils play at his best level and produce sublime Hot Shots, with a smile on his face. After a series of injury woes, Monfils has made a significant effort in the first quarter of 2019 to return to his peak performance days and his career-high of No. 6 in the ATP Rankings (7 November 2016).

The 32-year-old is up to World No. 19 on the back of his eighth ATP Tour title in Rotterdam (d. Wawrinka) and semi-final exits at the Sofia Open (l. to Medvedev) and Dubai (l. to Tsitsipas).