Andre Agassi isn't ready to walk away from tennis just yet.

Agassi defeated No. 8 seed Marcos Baghdatis of Cyprus 6-4, 6-4, 3-6, 5-7, 7-5 in a thrilling second-round matchup at the U.S. Open Thursday evening.

Andre Agassi defeated Marcos Baghdatis Thursday to advance to the third round of the U.S. Open.
(DON EMMERT/AFP/Getty Images)

Agassi emerged victorious in a dramatic encounter that lasted close to four hours in what will go down as one of the greatest matches in U.S. Open history.

Agassi, a two-time U.S. Open champion (1994 and 1999), previously announced plans to retire from tennis after this tournament.

With the New York crowd firmly behind him, Agassi jumped out to a two-set advantage before the pesky Baghdatis started to stage a comeback.

The 21-year-old Cypriot, a finalist at this year's Australian Open and a semifinalist at Wimbledon, won the third set and then fought back from a 4-0 deficit to win the fourth and force a decisive fifth set.

Baghdatis won the first game of the fifth and seemed to have things well in hand, but Agassi dug deep and took the next two games to regain the momentum.

The match took a unique turn in the ninth game with the score tied 4-4 as Baghdatis, bothered by cramps in his thighs, was forced to play through the pain. Baghdatis valiantly fended off four game points before finally succumbing in the 23rd point of the game.

Baghdatis received brief medical treatment during the changeover and fought off match point to tie it 5-5, but Agassi retook control by winning the next point and then broke the young Cypriot to win the match.

When it was over, they shook hands and embraced at the net before Agassi thanked the crowd.

"Tonight has been another example of moments you're not guaranteed in life," Agassi said.

Agassi will meet unseeded German Benjamin Becker in the third round.

Also on Thursday, No. 2 Rafael Nadal of Spain survived a tough challenge to qualify for the third round.

The reigning French Open champion defeated Peru's Luis Horna 6-4, 4-6, 6-4, 6-2 at Arthur Ashe Stadium.

Nadal won the first set and appeared poised to take the second before Horna broke serve twice to even the match at a set apiece. The hard-hitting Spaniard then saved a pair of break points when serving out the third set before rolling over Horna in the fourth and final stanza.

Nadal, 20, is trying to advance past the third round of the U.S. Open for the first time in his career.

In earlier second-round action, No. 6 Tommy Robredo of Spain lost the opening set before storming back to defeat Hyung-Taik Lee of South Korea 3-6, 6-3, 6-4, 6-1.

No. 11 David Ferrer topped Justin Gimelstob 6-2, 6-4, 6-1 and No. 15 Lleyton Hewitt defeated Jan Hernych 6-4, 6-2, 6-2.

Toronto's Daniel Nestor and partner Mark Knowles of the Bahamas opened their doubles campaign by defeating Tomas Berdych and Jan Hajek of the Czech Republic 7-5, 6-3.

Martina Hingis ousted early

On the women's side, former world No. 1 Martina Hingis stumbled out of the tournament with a shocking loss.

The eighth-seeded Hingis, who won the U.S. Open in 1997, lost her second-round match to unseeded Virginie Razzano of France 6-2, 6-4.

In eight previous appearances at the U.S. Open, Hingis' earliest departure was in the fourth round.

"It's not only that [Razzano] played well, but I didn't play good," Hingis said. "I was a little flat and tired mentally. It just wasn't my day."

Hingis has climbed back into the top 15 in the world in 2006 after taking off three years due to injuries. Hingis distinguished herself in Montreal earlier this month by reaching the final of the Rogers Cup, but could do very little to stop Razzano.

"I played my game," said Razzano, who lost both of her previous matchups with Hingis in straight sets.

Lindsay Davenport, another former U.S. Open champion, made an impressive statement on Thursday, taking only 40 minutes to squash Croatian Jelena Kostanic.

The 10th-seeded Davenport blanked Kostanic 6-0, 6-0 to breeze into the third round. The American star surrendered only 21 points in the match. It was the first love-and-love match at the U.S. Open since American Venus Williams shut out Croatian Mirjana Lucic in 2002.

"Some days, everything just seems to be working," said Davenport. "These days don't happen that often, so you have to be happy when they come your way."

Davenport, the 1998 U.S. Open women's champion, next plays No. 22 Katarina Srebotnik of Slovenia.

Many of the world's top tennis players also moved into the third round on Day 4 at the Open.

No. 1 seed Amelie Mauresmo of France defeated American Meghann Shaughnessy 6-4, 6-3.

Belgium's Justine Henin-Hardenne, the 2003 champion, quickly disposed of American teenager Vania King 6-1, 6-2.

The second-seeded Henin-Hardenne uncorked 22 winners en route to dispatching King. Third-seeded Maria Sharapova overwhelmed Emilie Loit 6-0, 6-1.

Other women's seeds to advance were No. 4 Elena Dementieva, No. 5 Nadia Petrova and No. 6 Svetlana Kuznetsova of Russia, No. 7 Patty Schnyder of Switzerland, and No. 9 Nicole Vaidisova of the Czech Republic.

In a minor upset, Russian Anastassia Rodionova defeated No. 29 Zheng Jie of China 7-5, 6-3. American Serena Williams beat No. 17 Daniela Hantuchova 7-5, 6-3.

With files from the Associated Press