World number two Roger Federer [Images] lamented what could have been after he lost a thrilling five-set final to Rafa Nadal in the Australian Open [Images] on Sunday.

Federer was seeking a record-equalling 14th grand slam title on Sunday at Melbourne Park but ran into a tenacious Nadal who pipped him to the title 7-5 3-6 7-6 3-6 6-2.

"This is one of the matches in my career where I feel like I could have or should have won," a glum-looking Federer, who also lost a classic five-set final at Wimbledon [Images] to Nadal last July, told reporters.

"But you can't go through your whole life as a tennis player taking every victory that's out there.

"You've got to live with those (defeats) but they hurt even more so like if you're that close, like at Wimbledon or like here at the Australian Open.

"So that's what's tough about it. But I have no regrets so it's all right."

Federer, who had hoped to equal Pete Sampras's [Images] record of 14 grand slam titles, converted just six of 19 break opportunities.

"I had, I guess, many chances," he said. "I mean, I was up a break in the first (set) twice.

"Yeah I had many chances. I missed them and they cost me dearly."

Federer also produced a poor service game, making just 52 percent of his first serves, and admitted it was a key factor in the game.

"I won a set against Rafa serving, what, 30 percent first serves?" he said.

"I got a great second serve (which is) very reliable normally (and) I hit some stupid double faults, but that's going to happen in a five set match usually.

"I tried to kind of get the grip on my serve but never really found the rhythm, which was a pity.

"It was a tough match. I don't think I served particularly well and I think that was the key to the match in the end."

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