WASHINGTON — It felt like Jannik Sinner had the upper hand through almost his entire match against Mackie McDonald.
Finally, after nearly three hours, Sinner could celebrate a victory and a tournament championship.
“When you’re up always with the score and then you cannot close it out, it’s not easy,” Sinner said. “I tried to somehow stay calm and work for my chances.”
Sinner became the first teenager to win an ATP 500 event, beating McDonald 7-5, 4-6, 7-5 to take the Citi Open title. It was a struggle for the fifth-seeded Sinner. McDonald fought off 10 set points before losing the first set, and Sinner failed to convert two match points while up 5-2 in the third.
McDonald rallied to make it 5-all in the final set, but he ultimately fell short. Sinner finally won when McDonald’s backhand went into the net, and he celebrated by holding up his racquet with one hand and a No. 1 sign with the other.
“I dug as deep as I could,” McDonald said during the on-court ceremony afterward. “Obviously, Jannik is a great young player and he pushed me really hard today, and I think I left it all out there.”
Sinner, who turns 20 on Aug. 16, won his third ATP title and second this year. He was the first Italian finalist in this tournament’s 52-year history, and he became the event’s third-youngest champion, behind 18-year-old Andy Roddick in 2001 and 19-year-old Juan Martin del Potro in 2008.
Teenagers had been 0-5 in ATP 500 finals since the category was created in 2009.
“When you see somebody is the youngest or whatever, I don’t put much weight on that,” Sinner said. “You know, there are a lot of players who have done much, much better than me. It’s not about who is the youngest or whatever.
“I just want to improve, working hard.”
McDonald, a 26-year-old American playing in his first ATP final, made Sinner work. The second set was the first that Sinner dropped in this tournament, and after the Italian went up a break early in the third, McDonald battled back.
Sinner broke McDonald’s serve again to end the match.
Although Sinner took the first set, McDonald set the tone for the match by fighting off all those set points. He withstood six of them with Sinner up 5-4, and the other four were at 6-5. McDonald had his serve broken three times in the set, and Sinner had his broken twice.
In the doubles final, Raven Klaasen of South Africa and Ben McLachlan of Japan beat Neal Skupski of Britain and Michael Venus of New Zealand 7-6 (4), 6-4.