As Gael Monfils played in the fourth round of the U.S. Open on Tuesday, it was impossible to tell that he was winning his match in straight sets or that he had not dropped a set in the tournament.
He spent most of his time between points muttering to himself in French, often while gesturing to no one in particular with his racket. He argued with the umpire.
On one or two points, he simply stopped playing. He returned one of Grigor Dimitrov's serves straight into the stands, seemingly on purpose.
The scoreboard, however, told the real story. Monfils beat the No. 7-seeded Dimitrov, 7-5, 7-6 (6), 7-5, lifting himself into the quarterfinals for only the second time in his eight U.S. Open appearances. In the brutal heat of Tuesday afternoon on the Arthur Ashe Stadium court, another straight-sets victory seemed like a gift from above, even if Monfils didn't appear to enjoy it much.
Afterward, though, he was all smiles.
"It is because I love to play here," Monfils said of his victory. "I have such a good feeling here. I just feel good. I am happy, so I deliver a good game."
Monfils' upset, coupled with a later victory by second-seeded Roger Federer on Tuesday night, sets up an entertaining quarterfinal showdown between Federer, the 17-time major champion, and the charismatic Monfils just a few weeks after the two faced off in a Masters series event near Cincinnati.
Federer dispatched No. 17 Roberto Bautista Agut, 6-4, 6-3, 6-2, using an impressive service game and a heavy reliance on net approaches. Federer also did not lose a point in his first two service games of the second set, winning 78 percent of his first-serve points in the match, with eight aces against Agut, whom he had never faced before.
"I was very happy when the match was over, because like this I know - it's done," Federer said. "Next time I play him, I know what to expect. Not like today."
Looking to his quarterfinal match, Federer said that Monfils has "top-10 potential."
"I think I can speak on behalf of so many players: We love watching him play," Federer said.
Monfils, the No. 20 seed, has always loved to play here. After his home country's French Open, it is his favorite Grand Slam tournament. He plays to the crowd with a showman's flair. His results have not matched that affinity, and he said that up until Tuesday, he had never won a match in Ashe Stadium.
"I would say this time I am maybe a little bit lucky," Monfils said. "I think I played good. But I haven't changed a lot. I played maybe more solid today, but I stay the same."
Against Dimitrov, Monfils showed off his refurbished game, less reliant on long, grueling points and more on quick-strike efficiency. He served well, with 14 aces, and lost his serve only once. He continued his trademark of running around many balls to get to his forehand, but his backhand was effective, too.
While Monfils sometimes unraveled in between points, he stayed composed while the ball was in play, which could not be said of his opponent. Dimitrov, despite his high seed, has not done spectacularly well in big matches. He reached the semifinals of Wimbledon this year, his best showing at a major, but in three previous Opens, he lost in the first round.
Dimitrov had a lead in the second-set tiebreaker and was serving to take command, but he sent two forehands wildly long to squander those opportunities, while Monfils dug in and battled back to win. In the third set, which contained some of the most acrobatic and thrilling points of the match, Dimitrov seemed poised to force a tiebreaker, only to spray several errors to reach break point before double-faulting on the final point.
"Where should I begin?" Dimitrov said. "Just a bad match for me. Didn't play as close to the way I wanted to, and I think it was a great stage for me to come out on there on the center court and perform my best. Just everything went the opposite way today.
As the Monfils-Dimitrov match was finishing up, the battle between No. 14 Marin Cilic and No. 26 Gilles Simon was just starting to get interesting. Neither man was particularly sharp, and Simon was struggling with back pain, which held him up several times during the first set. But it wound up being a taut five-set marathon, lasting 4 hours, 13 minutes, the fourth-longest match of the tournament so far.
The two men battled until the sun finally dipped below the stands, a welcome reprieve for players and fans alike. Cilic said he got his second wind in the fifth set, when he had five of his 23 aces to wrap up a 5-7, 7-6 (3), 6-4, 3-6, 6-3 victory.
Cilic reached his third U.S. Open quarterfinal since 2009, and his second straight at a Grand Slam event this year. He won on Tuesday even after committing 76 unforced errors against Simon.
"He's a grinder, counterpuncher, runs a lot and doesn't mind," Cilic said. "It was very, very good from my own side that I came back very strong in the beginning of the fifth."
Cilic will meet the No. 8 seed, Tomas Berdych, who blew through the 20-year-old Dominic Thiem in dominating fashion, 6-1, 6-2, 6-4. Berdych needed only an hour to take the first two sets over Thiem before polishing him off in 98 minutes.
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