OMNISPORT

Jo-Wilfried Tsonga said his revival in his US Open quarter-final loss to Marin Cilic was aided by the defending champion's let-down.

Tsonga forced a fifth set after losing the first two, but Cilic advanced to the last four in defence of his crown at Flushing Meadows - sealing a 6-4 6-4 3-6 6-7 (3-7) 6-4 victory on Tuesday.

The Frenchman, playing in just his second quarter-final at the US major, said the match was largely on Cilic's racquet, which only produced five unforced errors in the crucial final set.

"Well, the thing is he just dropped down [his level] a little bit, and, me, I just stay at the same level," Tsonga told a news conference. 

"It was not something better [from me]... it was quite the same level. And it just made the difference because he dropped a little bit."

Despite blowing a two-set lead, Cilic recovered to crunch 18 winners in the fifth set - and saved both break points he faced, including one when serving for the match.

"He just hit the ball a little bit more properly than me at the right moment, and that was a huge difference at the end, because he just made it. He just made it," Tsonga said.

Tsonga's serve had not been broken heading into the last-eight clash, but Cilic earned one in each of his winning sets to prevail.

The 19th seed said he was unhappy with his service game, winning only 74 per cent of points behind his first ball - a personal low for the tournament.

"I think the serve is the only thing you know about yourself when you play tennis. If you make it right, you make it right," the 30-year-old added. 

"Nobody can touch you when you serve. Nobody can disturb you. You have the ball in the hand. 

"And today I just served, I would say, very bad compared to the other day."