ATP season-ending Masters Cup has been further hit after just the second day's competition at the 4.45 million US dollars men's tennis finale, as Rafael Nadal and Andre Agassi, seeded 2-3 in the eight-man draw, announced in Shanghai on Monday to pull out due to injury.

The reigning French Open champion Nadal, ranked second in the world, withdrew from the event before kicking off his Masters debut in Red against Argentina's Gaston Gaudio, citing a left footinjury.

And the eight-time Grand Slam winner Agassi decided to join the19-year-old after losing in straight sets to Russian tennis upstart Nikolay Davydenko in another Red Group round-robin matchup.

Mariano Puerta, alternate in Shanghai for the ATP year-ending event, was called up to fill in the vacancy left by Nadal, joiningcompatriots Gaudio, Guillermo Coria and David Nalbandian in the event as the record fourth Argentine in a Masters Cup. In the night's singles match, Gaudio beat Puerta 6-3, 7-5.

On the men's doubles part, third-seeded Zimbabwe duo Wayne Black and Kevin Ullyett came back to win over sixth seeds Michael Llodra and Fabrice Santoro from France 3-6, 6-3, 6-4 in earlier play, and second-seeded Swede Jonas Bjorkman and Belarus's Max Mirnyi lost 6-2, 6-4 to Stephen Huss of Australia and Wesley Moodie from South Africa.

Withdrawals from top seeds further hurt the injury-hit Masters,as world number three Andy Roddick and the fourth-ranked Lleyton Hewitt had announced to skip the tournament even before it unveiled.

A lower back injury sidelined former ATP race leader Roddick. He sustained the injury two weeks ago during his quarterfinal match against David Ferrer at the BNP Paribas Masters in Paris. David Nalbandian was elevated from his alternate status to a berthin Shanghai.

Hewitt, the two-time Masters Cup champion, announced his withdrawal from the circuit finale due to impending fatherhood, ashe and his wife Bec Cartwright are expecting their first child within the next two weeks. Gaudio, ranked 9th after the ATP Masters Series Paris, then qualified for the year-ending tourney.

The withdrawal from all-time great Agassi was unexpected thoughthe 35-year-old played totally "un-Agassi" tennis in his showdown against Davydenko.

"With the state of my ankle right now, there's no chance for meto be able to play again," said Agassi at a post-match news conference after losing 6-4, 6-2 to the Russian tennis upstart.

"This is, for me to go out on the court to play like this, nobody wants to see it," added the oldest player in the ATP finale. "It's very dangerous and risky for my future to be ready for anything in the next four or five weeks. So this is just an unfortunate setback."

Agassi was broken for three times against five aces from his 24-year-old opponent.

Agassi committed 3 double faults and 23 unforced errors against14 winners and Davydenko cracked just two more winners against 2 double faults and 27 unforced errors.

Besides fitness problem, Agassi imputed his lack of form to long absence from the court.

"When you haven't played in so long, I couldn't really hit balls for a couple of months because of my sprained ankle," said the American, who qualified for his fifth Tennis Masters Cup in six years and finished in top 10 for 16th time this season in his 20-year career.

"Just from serving, in the last week of trying to get ready, itwas just a little stiff and sore. But the movement is more of an issue.

The 60 career title holder, ranked 5th in the ATP Entry Rankings, ruled out an unexpected bad status, and said: "Last few days, it's arguably not getting worse, so I have to try and see and give it a chance to push through.

"But it has way too much effect on my movement. I'm scared to hurt it worse. It's still very painful, especially after 35, 40 minutes of being on the court."

"It doesn't do anybody any good for me to be out there, except for my opponents. That's it," he added.