Watch: Gael Monfils gets angry, tanks point in U.S. Open win

NEW YORK -- Ah, the enigmatic and unpredictable Gael Monfils. The Frenchman, ranked No. 24, beat No. 8 Grigor Dimitrov on Tuesday 7-5, 7-6 (6), 7-5 to advance to his second Slam quarterfinal of the year at the U.S. Open. But the straight-set win was nearly complicated in the second set when Monfils' form began to dip and let his frustration get the better of him. After building a 4-2 lead Monfils' forehand began to fail him and Dimitrov broke back and was about to serve for a 5-4 lead. Monfils was so mad he just didn't want to play anymore, and effectively conceded the final point in Dimitrov's service game by returning serve at the service line:

"Second set, yeah, I just get a bit pissed," Monfils said. "I finish. Then I was sorry for Grigor, because I was in front, and [I] was like, Just serve. Because obviously I give you the game, so it's okay."

Monfils said when he's not having fun he tends to check out of matches. "For me tennis is a sport, you know," he said. "It's not a job, it's a sport. Sometime if I'm fed up with that, [I] just leave it. For me, I don't know if it's bad to say it and for sure I will use like bad words in English, but it's like, you know, [I] don't give a s***. It's like okay, next one.... It's like if I'm not happy, it's okay. I want just to be happy. If I'm not happy, fine. Have it, you know."

The second set eventually went to a tiebreaker and this time it was Dimitrov's turn to blow a lead. Up 6-3 in the tiebreaker, the Bulgarian lost five consecutive points to lose the set and then the match. 

(h/t Tennis.com)