Jannik Sinner staves off inspired McDonald for biggest career title at Citi Open

WATCH: Sinner won his first ATP 500 title in three grueling sets over McDonald at the Citi Open on Sunday.

This year’s Citi Open was a tale of four stories. It began with Rafael Nadal’s first trip to Washington, D.C., and his first bike ride through the National Mall. When Rafa lost early, 20-year-old Jenson Brooksby picked up the slack by using his clever, unorthodox game to reach the semifinals.

Brooksby finally faltered, but not before handing the baton to another American, Mackenzie McDonald, who played the coolest, calmest, most collected tennis of his life to reach his first ATP final. Finally, after three sets and nearly three hours on Sunday, McDonald gave way to Jannik Sinner in a 7-5, 4-6, 7-5 championship match.

Sinner’s story is the least surprising of all four, but it may be the most important one for the future of the men’s game. The Italian is just 19, but this was his fourth final and his third title. He dropped only one set, and beat three Americans—McDonald, Brooksby, and Sebastian Korda—along the way. Sinner is younger than each of them, but when those matches were over, he was the one who gave his vanquished opponents encouragement, as if he were the elder statesman. Sinner acts like a man who knows there’s a spot waiting for him in the Top 10, and who could doubt him?

That said, as his performance in the final proved, he’s not close to realizing his full potential yet. Sinner was the more powerful player: When he leaned on his backhand or opened up and rifled his forehand into the corners, even the speedy McDonald could keep the ball coming back for only so long. For the most part, Sinner was the better player, but he wasn’t always the better player when he needed to be. It took him 11 set points to win the first set. Up a break point at 3-2 in the second, with a chance to run away with the match, he drilled a backhand into the net and gave a tired-looking McDonald a second wind.

In the third, Sinner gathered himself and built a 5-2 lead, before faltering again and letting the American get back to 5-5. Finally, he closed with a love hold and won a back-and-forth last game for the title. McDonald showed a lot of poise in the final, but he was ultimately at the mercy of Sinner’s machine-gun ground game.

There are periods when Sinner, with his pure strokes and casual power, beats his opponents to the punch every time. No matter how quick or experienced the other guy is, there’s nothing they can do with his ever-more-rapid responses. But then there are periods when that power goes awry and his shots inexplicably begin to find the tape—or fly five feet wide. Sinner can change pace, play safely, and put more air under the ball, but that’s not where his instincts lie. His instincts are to get the first punch in, even if he swings wildly and misses.

Should this make his colleagues and opponents on tour feel better, knowing that he’s erratic, and that if they stay with him, he’ll eventually miss? Or should this make them feel worse, knowing that he still has many years to refine and add elements to his attack, and to mature strategically? Unfortunately for the rest of the tour, I’d say the latter is more likely to be the case.

Sinner may still be a wild swinger, but he seems to a have methodical, even-keel mind, one that will keep doing whatever it takes to improve. The fact that he’s 19, and that he won his third—and most consequential—ATP title while still having so much room to improve is probably the biggest, and scariest, story of all from this year’s Citi Open.