Roger Federer says a caravanning holiday around the Swiss countryside has left him feeling the best he has "in years" before the US Open.

Federer, 38, is going for a record sixth Open era men's singles title in New York.

The 20-time Grand Slam champion, who last won at Flushing Meadows in 2008, says the trip helped him process his Wimbledon defeat by Novak Djokovic.

"Overall, if I look back, I'm very happy," Federer said.

"The way I played at Wimbledon is going to give me some extra confidence.

"This is probably the best I've felt in years coming into the US Open which is encouraging."

Federer beat long-time rival Rafael Nadal in a memorable semi-final at the All England Club, then lost to top seed Djokovic in a historic fifth-set tie-break after holding two match points.

"I struggled a little bit the first couple days. At the same time I was caravanning with my kids. I didn't have that much time thinking about all the missed opportunities," Federer, who lost to Australian John Millman in the US Open last 16 last year, said at Flushing Meadows on Friday.

"I was setting up tables and organising my life for my four children, driving around the beautiful countryside in Switzerland.

"Sometimes you have flashbacks, things like 'oh, I could have done that, should have done that'.

"The next day you're having a glass of wine with your wife thinking 'the semis was pretty good, even the finals was pretty good'. You go in phases.

"It took me maybe a couple of days to get those things out of the system, like it takes with everything.

"I've had a great run through the clay, on the grass as well, that I was not going to be too down on myself. I hope it's going to help me for here."

Federer won all five of his US Open titles consecutively between 2004 and 2008, putting him alongside Jimmy Connors and Pete Sampras in terms of victories since the Open era was introduced in 1968.

"I'm not putting extra pressure on myself," the third seed, who will play a qualifier in the first round, said.

"I know it's going to be tough. I'm not coming in as the overwhelming favourite like maybe I did back in 2006 or 2007.

"I'm very much aware of how I need to approach this tournament mentally."

Federer has only played once since his Wimbledon loss, suffering his quickest defeat in 16 years when he was beaten 6-3 6-4 by Russian Andrey Rublev at the Cincinnati Masters.

"It might be a good thing that I lost early, who knows," Federer said.

"Maybe I needed to get knocked down in Cincy, get my act together, train hard. That's what I did. Now I'm ready for the US Open."