By Pritha Sarkar

NEW YORK (Reuters) - When Roger Federer flicks back on his 2008 memoirs he will probably want to read up on his Sept 8 entry before anything else.

After the first eight months produced some memorable, if painful snapshots of his career, he finally rescued what had been a rather lean season in his own high standards by winning a fifth successive U.S. Open trophy on Monday.

Until his triumph in New York, a 6-2 7-5 6-2 win over Briton Andy Murray, fans and pundits alike were predicting Federer's swift demise from the top of the game but the Swiss master had his own analysis on his year to date.

"It's better than 2003 when I made the breakthrough and won Wimbledon," a rather fresh-looking Federer told an invited group of journalists on Tuesday despite sleeping for only 20 minutes following his triumph.

"I lost in the first round in Paris (in 2003) so obviously it's way better. If it's a good, a great or a super year, it doesn't matter for me. I got the grand slam I wanted.

"I always say one grand slam (a year) in my eyes saves a season. That's definitively what it did. But 'saving a season' doesn't sound right. I proved to myself that I was doing the right things.

"I played excellent towards the end of the tournament and it's the first time I felt invincible again for a change."

"Winning a fifth U.S. Open is a dream come true. You don't think a player needs five but it does create something incredible for your legacy and makes you very proud," added Federer, the first man since 1924 to win five in a row here.

While there is no doubting Federer's legacy, he is still irked by the comments made by some former champions, including Swedish great Bjorn Borg, who were ready to write him off after his three-set mauling by Rafael Nadal in the French Open final.

"I was quite shocked with what happened at Wimbledon. In Paris everybody was saying I was going to win Paris and then I come to Wimbledon (and they are saying) basically I'm not going to win a thing anymore. I thought that was a bit extreme," said Federer, who suffered from a bout of glandular fever at the start of the season.

FINAL FOE

The Swiss had wanted to silence his critics when, as five-times Wimbledon champion, he reached his sixth consecutive final at the All England Club.

But with his bogeyman Nadal once again as his final foe, many predicted the Spaniard would steal Federer's crown.

Nadal did end Federer's reign but it turned out to be a heart-stopping five-set epic which has since been hailed as the greatest match ever.

Although Federer still finds it hard to accept that he lost, he feels the match achieved one of his life-time ambitions.

"I was aware of how incredible the match was. Unfortunately there had to be a winner. From my point of view many left feeling sorry for me instead of being happy for Rafa. Which hurts," said Federer, whose 4-1/2 year stint as world number one was also ended by Nadal last month.

"But at the same time Wimbledon was great. I felt tennis went up a notch and that's what I've been trying to do for five years since I was number one in the world. Trying to get tennis more popular& and that Wimbledon final has finally achieved what I have been wanting to."

Other long-term goals include winning a gold medal in singles at the London 2012 Olympics, the Davis Cup for Switzerland and claiming an elusive French Open crown. Having turned 27 last month, Federer feels he has many years to fulfill those dreams and is also keen to test his skills against the future generations in the sport.

"I live and breathe tennis. I get away from tennis but subconsciously I always have it right there. It's what I love doing the most that's why I'll do anything for it," said the world number two, who won a doubles gold at the Beijing Games.

"I'd like to play through as many generations as possible. It's so fascinating to see in golf when the greats are still around to face the juniors. What I'm striving for is longevity ... and I feel so much better physically today than I ever have."

(Editing by Dave Thompson)