Warhorse Lleyton Hewitt steals the show at US Open

Australian warhorse Lleyton Hewitt battled to a five-set US Open win over Argentine sixth seed Juan Martin Del Potro Friday, relegating Andy Murray, Novak Djokovic and Serena Williams to supporting roles.

The 2001 champion defeated the 2009 winner, 6-4, 5-7, 3-6, 7-6 (7/2), 6-1 in the tournament's biggest shock to date.

Hewitt, 32 years old and down at 66 in the rankings after a lengthy battle with injuries, served up a trademark warrior-like performance that recalled his golden days when he was world number one and Wimbledon champion.

It was his 32nd career five-set victory and gave him a third-round match-up with Russia's Evgeny Donskoy, the world number 102.

"I was really pumped up after I won my first match because I knew I would have a chance to play on Arthur Ashe Stadium," said Hewitt after his four-hour, three-minute win.

"I don't know how many years I have left to play and I was hankering to get out on this court again and put on a show."

Del Potro, still bothered by a wrist injury, was beaten in his second successive four-hour match.

"He's a great champion and a great fighter," said the big Argentine.

Hewitt, playing in his 13th US Open after having made his debut in 1999, hit 42 winners, one more than del Potro, who committed 70 unforced errors, a bleak statistic which eased the impact of the Australian only converting eight of 18 break point chances.

Hewitt's pyrotechnics overshadowed the progress into the third round of defending champion Murray and world number one Djokovic, as well as women's champion Williams, who made the last 16.

Murray, the third seed and Wimbledon champion, survived his first scare of the US Open, beating Argentina's world number 81 Leonardo Mayer, 7-5, 6-1, 3-6, 6-1 and goes on to tackle Germany's Florian Mayer for a last-16 spot.

Murray fired 28 winners while the Argentine hit 49 unforced errors.

"It was a very tough match," Murray said of an opponent who like him was born on May 15, 1987.

"Both of us ran a lot and it was very humid. I'm just glad I was able to put it together and pull it out in the fourth set."

Djokovic, the 2011 champion, survived a first-set wobble before racing away with 12 of the last 14 games to defeat Germany's Benjamin Becker 7-6 (7/2), 6-2, 6-2 after saving two set points in the 10th game of the opener.

Djokovic, bidding to reach the final for a fourth successive year, sent down 13 aces and 40 winners against the 32-year-old Becker.

"Becker is a quality player and he should have won the first set. I was fortunate to come out of it, but after that I felt more comfortable on the court," said Djokovic, who next plays Portugal's Joao Sousa.

Czech fifth seed Tomas Berdych, who defeated Roger Federer on his way to the semi-finals last year, made the third round by seeing off America's Denis Kudla 7-6 (7/3), 7-6 (7/3), 6-3. He next meets French 31st seed Julien Benneteau.

In the women's event, four-time champion Williams eased past Russian-born Kazkhastan player Yaroslava Shvedova, 6-3, 6-1.

Williams, who has dropped just eight games in three rounds, is chasing a 17th Grand Slam title and next plays compatriot Sloane Stephens, who beat her in the Australian Open quarter-finals in January.

Chinese fifth seed Li Na hit 11 aces in a 6-2, 7-5 victory against teenager Laura Robson, avenging her loss to the Briton at the same stage last year.

The 31-year-old Li goes on to face Serbian ninth seed Jelena Jankovic, the 2008 runner-up, for a quarter-final spot.

"I was really happy how I was hitting on the court," Li said. "And I thought I served really well."

Li's best US Open performance was a run to the quarter-finals in 2009, one round better than Polish third seed Agnieszka Radwanska, who has stumbled at the fourth-round stage on three occasions.

The 2012 Wimbledon runner-up made the last 16 once again with a 6-4, 7-6 (7/1) win over Russian 32nd seed Anastasia Pavlyuchenkova, a quarter-finalist in 2011.

Radwanska now faces Ekaterina Makarova, the Russian 24th seed who clinched a 6-4, 7-5 win over German 16th seed Sabine Lisicki, the Wimbledon runner-up.