Roger Federer has warned his rivals he feels as good as ever as he bids for a sixth US Open title in seven years at Flushing Meadows.
Federer has won just two tournaments this year, losing his world No.1 ranking to Rafael Nadal and crashing out of Wimbledon in the quarter-finals to Tomas Berdych, the six-time champion's earliest exit at the All England Club since 2002.
The Swiss star took a six-week break after Wimbledon, returning to the tour in Toronto where he lost to Britain's Andy Murray in the final, but bounced back with victory in Cincinnati the following week.
And the 29-year-old clearly feels reports of his demise have been greatly exaggerated as he begins his campaign for a 17th Grand Slam title against Argentina's Brian Dabul.
"Mentally I'm very fresh," said Federer, who was just two points away from a sixth straight title before losing to Argentina's Juan Martin Del Potro in last year's final.
"I didn't play for six weeks after Wimbledon, I had a good vacation, spent some time in Switzerland with friends and family. From the mental side I have no problems whatsoever."
"Physically I feel the same thing. I feel as good as I can feel prior to a Grand Slam. I have no niggling injuries, no pain anywhere."
"In Toronto I really had a lot of muscle pain, my arm, my wrist, my chest, my shoulder. Coming back right off the bat after six weeks and playing such tough matches early on was tough on the body."
"I got a little bit lucky in Cincinnati with a walkover against Kohlschreiber. That gave me that extra day of rest, next thing I knew I never looked back and didn't have any physical problems any more. Here I am, I've had good preparation and am ready to go."
Asked about the perception that his powers are on the wane, Federer added: "I was winning one or two Slams a year and I was on the downslide so you can't really take it too serious really, to be quite honest."
"You can't win 12 tournaments every season. That's clear to me. I spoiled myself by playing so well and you just prepare for the times when it's not winning 12 a season. If it's two or four or six it's still a good season depending on how you're feeling, how you're evolving as a player. I was always making sure I tried to get better."
"I also had some problems. I had mono (glandular fever), I've had a lung infection, I've had a bad back. It's all been on a lower level but maybe at times I should have just taken a rest instead of playing."
"But I'm not scared of taking losses. I wanted to know where I stand and the only place I could find out is at tournaments. Hopefully I'm not losing in the first or second round and if people think 'Oh, he's not the same,' well that's not something new because I knew I was not the same player for a few events."
"But it gets over-rated sometimes. Then I stop reading the press when it becomes that kind of an atmosphere."
Also in first-round action on Monday is American Andy Roddick, who has also been suffering from glandular fever this year but is relieved to be over the worst of it.
"Some days were a lot worse from others," admitted Roddick, who takes on France's Stephane Robert.
"I got back from Wimbledon and was trying to do some track work."
"I don't think I've ever opted out of a workout before in my life and I had two or three in a row where it just felt kind of off. It was frustrating and had me wondering 'Am I out of shape? What's the deal?'"