Young American Andy Roddick revealed a new respect for tennis' older generation after his epic five-hour triumph over Younes El Aynaoui at the Australian Open.

The 20-year-old prevailed 4-6 7-6 4-6 6-4 21-19 after 40 games in the fifth set - the highest number of games in a final set of a Grand Slam match.

It topped the marathon 20-18 effort of Mark Philippoussis and Sjeng Schalken at Wimbledon in 2000, with the total number of games in both matches reaching 83.

I think it was just pure fighting - this was more about heart Andy Roddick

The fifth set lasted two hours and 23 minutes, almost as long as the first four sets combined, making it one of the longest in the history of professional tennis.

Afterwards Roddick and the 31-year-old El Aynaoui embraced like long lost friends.

"My levels of respect for him just grew and grew throughout the match and I'm pretty sure it's vice-versa," Roddick said.

"I don't even remember talking to Younes before the match but if we see each other 10 years down the line we'll know we shared something pretty special.

"He's 31-years-old, he's out there five hours, and he's still standing at the end. It's very impressive. I don't think I'll be able to do that when I'm 31.

The pair embrace after an epic struggle

"This has proven that even the old guys can still play some ball."

Both players had their chances to win the decider and both had to fight back from the brink of defeat.

El Aynaoui had a match point in the 10th game of the final set but missed it.

Roddick served for the match in the 22nd game but was broken.

Finally, in the 39th game, El Aynaoui put a forehand long to lose his serve and this time Roddick seized his chance.

"Strategy was out the door late on in the fifth set," Roddick added. "I think it was just pure fighting. This was more about heart."

Roddick admitted his fourth round win over Mikhail Youzhny, when he fought back from two sets down to win in five, had proved a valuable psychological asset.

"I don't think you can train for something like this," he added. "But I can honestly say that coming back the other day did help my confidence for this one.

"I was just thinking 'OK, I have done this before.'"