Unheralded Kristian Pless stole the show on a star-studded evening at the Chennai Open as he knocked out the second seed David Nalbandian of Argentina in the first round of the ATP event on Tuesday night.

In winning 2-6, 6-3, 7-5, in two hours and 22 minutes, the Dane posted his first victory over a top-10 player.

Earlier in the day, Indian wild card Karan Rastogi pulled off a stunning victory over higher-ranked Thiago Alves of Brazil to earn himself a meeting with top seed Spaniard Rafael Nadal in the second round.

2003 champion and Asia No 1 Paradorn Srichapan of Thailand got the better of qualifier Simone Bolelli (Italy) 7-6 (5), 6-4 in another late night match.

Nalbandian, who celebrated his 25th birthday on Monday, said the tendonitis in his knee affected his movement on court. Though the two have had close encounters, the Argentine leads 2-0 in the head-to-head, getting the better of Pless in the first round in Beijing in 2004 and 05.

"I was feeling pretty good in the first set and thought I would finish the match in two sets," said Nalbandian.

"After the match went into the third set the tendonitis didn't help, I could not hit the ball as heavy or deep as I did in the first set."

World number 9 Nalbandian was in a league of his own in the first set, racing ahead with breaks in the third and the fifth games to win the set in 38 minutes.

The Dane was again put to the sword in the first game of the second set, but after five deuces and three breaks points he finally held serve and went on to break Nalbandian in the second game after the Argentine served two double faults.

With both players struggling with their serves, five of the games in the second set went to deuce. Despite being pushed by Nalbandian, Pless was able to serve out the set 6-3.

Pless was slowly catching up with the Argentine; he served five aces in the second set, but would usually follow up a hard-earned point with an unforced error. Fortunately for him Nalbandian wasn't keeping a tab on errors either.

"He made some easy mistakes in the second set and that got me going," said Pless, looking back on how he had sneaked a foothold into the match.

"Both of us did not serve well, that's the reason so many games went to deuce. David and I have played some close games together but he has won all of them; this time it was my turn."

Pless served with greater pace after the first set, and banged in five and six aces in the second and third sets respectively. He returned a lot better in the next two sets, but a more telling statistic was that he won 64 per cent of the points on his second serve ( 56 percent in the second and 81 in the third) to 38 per cent for Nalbandian.

The third set also ran very close, with Nalbandian winning the first three games and Pless matching him in the next three. The players mixed the ordinary with the brilliant to keep the sizable crowd on the edge of their seats.

A superb backhand cross-court from Pless gave him the vital break in the eleventh game of the deciding set. He then started with an ace and closed the game at love when a Nalbandian forehand just dipped wide.