By Pritha Sarkar

LONDON (Reuters) - All it took was "one stupid move" for Roger Federer's season to fall into an abyss.

For much of his career, the seven-times Wimbledon champion had been blessed with a body that seemed bullet-proof against the aches, pains and injuries suffered by most top athletes.

But one false move by the man usually known for his gliding footwork while running a bath for his six-year-old twin daughters sparked a chain of bad luck that has left Federer in a situation that is completely alien to him.

For the first time since 2000, the 17-times grand slam champion, who required surgery on his left knee in February to repair a torn meniscus, arrived at Wimbledon without winning a title in the first six months of the year.

"I was very, very sad, just because I thought I was going to be lucky not having to do surgery in my career. I was doing so well all of last year," the Swiss third seed, who reached the Wimbledon and U.S. Open finals last year, told reporters on Saturday. 

"I was great at the Australian Open. Felt good throughout," added Federer, who was beaten by world number one Novak Djokovic in the semi-finals.

"After that, everything changed.

"The next day, one stupid move, the season's been completely different than what I expected it to be."

Coming into grasscourt major last year, Federer had won four titles with a 34-6 win-loss record from 10 tournaments.

Twelve months on and the 34-year-old has played only six events in 2016, and his 16-6 win-loss record will raise doubts about his ability to last five sets in a season beset with injury and illness.

Not only did the knee surgery throw a curve ball into the season, Federer has also been laid low with a viral illness and he was forced to pull out of the French Open with a back injury.

"Going into surgery was difficult. That's when it hit me," said Federer, whose absence from Roland Garros ended a streak of appearing in a record 65 consecutive grand slam tournaments.

"I got really disappointed and sad about it because that's when I understood what the road was going to look like."

While the back injury was a nuisance, the enforced absence from Paris allowed Federer to concentrate on his favorite time of the season and he played an extra grasscourt tournament in Stuttgart in addition to his traditional Wimbledon warm-up in Halle.

"I felt I had to stop everything by not playing Paris... just reset from there and make another push for Wimbledon, which was great," said Federer, who was sporting a white t-shirt emblazoned with a red double-decker bus sandwiched between SW19 lettering.

"This back has won me 88 titles, so I'm okay with that back. It's okay if it messes around with me sometimes," he added.

"That's why the decision not playing Paris was very easy to take because it was for Wimbledon, it was for the rest of the season, it was for my life, it was for the rest of my career."

(Editing by Ed Osmond)