NEW YORK — Roger Federer has incredible mental toughness and the Swiss great may have to lean on that attribute more than ever at the US Open if he plans to show the tennis world he has moved on from last month's Wimbledon heartbreak.

Rather than arriving at the Aug. 26-Sept. 8 US Open fresh off collecting a 21st Grand Slam title, Federer is instead left to wonder what could have been after failing to convert two championship points on his own serve in the fifth set against Novak Djokovic.

For Federer, who became the first man since 1948 to lose a Wimbledon singles final after holding match points, the loss was the cruelest of his career given it came at the All England Club where he has triumphed eight times before.

"I know what he's feeling," 2003 US Open champion Andy Roddick, who lost four Grand Slam finals to Federer, told Reuters. "It's a tough road back from such a tough loss.

"But he's always been the best at rebounding and kind of brushing it off and getting on to business and we will see if he can do that this time."

Roddick, who was one point away from serving for the title in the 2009 Wimbledon final which Federer ended up winning 16-14 in the fifth set, said there is no magic trick the Swiss can pull but he may find some comfort playing under the lights at the year's final Grand Slam.

"You can be as disappointed as you want but when you step out into Arthur Ashe Stadium at night with the lights on, New York has its eyes on you, hopefully that stirs up some emotion, some motivation," said Roddick.

"Kind of maybe reset. Not really think backwards but kind of look forward to the next two weeks.

"He's as professional as they have ever come so who am I to tell him what he should be doing? He has 20 slams for a reason."

The Wimbledon loss denied Federer a golden opportunity to further distance himself from his closest pursuers on the all-time Grand Slam list with Rafael Nadal second with 18 and Djokovic third at 16 going into his US Open title defense.

"It's not easy. Especially in the context of history as it applies to those three guys with 20, 18 and 16 slams," Roddick said of Federer having to move on from such a tough loss.

"Those titles matter, they could potentially be the history-making matches and slams won. But if there is anyone who can rebound it'll be Roger."

Since Wimbledon, Federer has played only one US Open tune-up event in Cincinnati where he suffered a shocking third-round humbling by Russian qualifier Andrey Rublev in 62 minutes – his quickest defeat for 16 years.

Federer would surely have loved to have made a deep run to move on from Wimbledon but despite the Cincinnati setback, his confidence is anything but shaken despite playing just two hardcourt matches in the lead-up to the US Open.

"I played 45 matches this year, so I think I should be fine," a smiling Federer said in Cincinnati last week when asked if he was concerned about not getting enough hardcourt matches in before heading to Flushing Meadows. — Reuters