© Peter Staples/ATP Tour

Juan Martin del Potro wins his 2019 season opener in Delray Beach.

Delpo Back To Winning Ways

Argentine kicks off his 2019

He'll want to clean up around the edges, including bolstering his match fitness, but Juan Martin del Potro will overall be pleased after winning his season opener 6-3, 7-5 against Japan's Yoshihito Nishioka on Tuesday at the Delray Beach Open presented by VITACOST.com.

The top seed seized enough of his chances (3/7 on break points), and although he wore a bandage on his rehabbed right knee and admitted to feeling some pain, Del Potro darted freely around the blue courts he's come to know well.

“It was a tough first round because Nishioka is a solid player from the baseline. But I played well in specific moments of the match,” Del Potro said. “I need to keep working hard on my legs because I felt tired at the end of the second set, but that's normal for [right now].”

Del Potro will face a much bigger test – literally and figuratively – when he plays 6'11" Reilly Opelka for a place in the quarter-finals. The American won his maiden ATP Tour title at the New York Open on Sunday, and the 21-year-old stayed hot, beating countryman Tennys Sandgren 6-4, 6-0.

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Del Potro, No. 4 in the ATP Rankings, hadn't played a match since 11 October, when he fractured his right patella at the Rolex Shanghai Masters. He missed the Rolex Paris Masters and the Nitto ATP Finals to finish 2018, and the Australian Open to start this year.

But, unfortunately for Del Potro, opening his season in South Florida has become somewhat of a tradition. Tuesday night marked the third time (2016, 2017) he has started his year at the ATP 250, and all three times he's celebrated a successful debut. 

The 2011 champion raised his level – and the mph on his forehand – to break in the eighth game and served out the opening set. Del Potro stumbled briefly in the second – blame his lack of matchplay – dropping his serve after breaking Nishioka.

But the Japanese left-hander sailed a backhand long on break point at 5-5 to hand Del Potro the break, and he served it out behind some of his best baseline play of the night.

“I didn't feel really well on court, but I think that's very normal for [right now]. I'm looking forward to feeling better in the next round,” Del Potro said. “I need time to get better, to feel confidence with my knee, with my body.”

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Defending champion Frances Tiafoe of the U.S. was upset by Brit qualifier Daniel Evans 3-6, 7-6(1), 7-5. "It was difficult conditions. I was just fighting as hard as I could," Evans said.

Tiafoe was two points away from winning at 6-5, 30/30 in the second set, and led 4-1 in the third. “Very frustrating, very frustrating,” Tiafoe said. “I definitely shouldn't have lost tonight. I probably rushed on big points, instead of working the point a little more.”

Three-time semi-finalist (2012, 2013, 2014) John Isner saved all four break points and hit 23 aces against Canada's Peter Polansky to advance 6-3, 7-6(4). The second-seeded Isner will meet Slovakian Lukas Lacko, who knocked out Japanese qualifier Yosuke Watanuki 6-4, 6-4. "The first match out in the heat and humidity is always pretty tough," Isner said.

Steve Johnson, the fourth seed, fought off Jason Jung of Chinese Taipei 7-6(3), 6-4 to setup a second-round meeting against Italy's Paolo Lorenzi, a winner against American qualifier Tim Smyczek 7-5, 6-3.

American Jared Donaldson, playing in his first match since 6 August, fell short against Spain's Guillermo Garcia-Lopez 2-6, 6-3, 6-3. Donaldson, who played at the 2017 Next Gen ATP Finals in Milan, was sidelined with tendinitis in his right knee.