Second seed Andy Roddick was knocked out of the Madrid Masters in his first match as he lost 3-6, 7-6, 7-6 to big serving Croat Ivo Karlovic on Wednesday.
Karlovic, the tallest player on the ATP circuit at 2.08 metres, set out his stall with six straight aces in his first two service games before Roddick capitalised on his opponent's errors to break and take the first set.
The second set went with serve, however, and Karlovic took the tiebreak 9-7 with his booming serves and reach at the net constantly unsettling the American.
The story was repeated in the third set and the Croat won the second tiebreak 7-3 to wrap up victory in the second round match. He now plays 14th seed Dominik Hrbaty.
Roddick said: "This is probably the best I have played against him. I don't think I could have played any better.
"He is always uncomfortable to play against and definitely played much better particularly with his volleying."
Top seed Rafael Nadal overcame Romania's Victor Hanescu 7-6, 6-3 in his opening match to book a place in the next round.
World number two Nadal started slowly, perhaps showing the effects of the tendonitis he has been suffering in his knees, and Hanescu broke his serve in the first game.
The Spaniard had to work hard to break back in the sixth game and then recovered from 3-0 down to win the tiebreak 7-5.
Nadal stepped up a gear in the second set and two breaks of serve brought him victory.
He will now play countryman and 13th seed Tommy Robredo, who overcame another Spaniard Carlos Moya 6-4, 3-6, 6-1.
Nadal said: "My knee was good enough. I was a little nervous early on but it gave me no problems while I was playing.
"The medical staff say I am still not 100 percent but I felt confident and was very pleased with my performance.
"We will have to see how things go after the tournament before making a decision about next week in Basel."
MISERABLE RUN
Gaston Gaudio's miserable run of form continued after he became the first seed to tumble out of the tournament earlier in the day following a 7-6, 6-2 defeat by Jose Acasuso.
Acasuso won the all-Argentine duel with the seventh seed to earn a third round match against Czech Radek Stepanek, who edged out British number one Tim Henman 6-4, 1-6, 6-3.
"I am not really worried by the defeat," said Henman who lost to Stepanek in Vienna last week. "I just need more match practice. It's not my technique that's letting me down. Overall I am excited about my game and playing pain-free.
"I am looking forward to starting with a clean slate next year."
Croat Mario Ancic, the 12th-seed, was the second seed to fall as he went down 1-6, 6-4, 7-6 to Olivier Rochus. The Belgian will face Ivan Ljubicic, the eighth seed, in the third round following his 6-3, 7-6 win over Alberto Martin.
Third seed Nikolay Davydenko made short work of Slovakia's Karol Beck, winning 6-4, 6-1 to set up a meeting with American Robby Ginepri.
Fourth seed Guillermo Coria, who has reached two Masters Series finals before losing both to Nadal, stayed alive with a 6-3, 6-4 win over Christophe Rochus and will meet Chile's Fernando Gonzalez.
Argentine sixth seed Mariano Puerta scrapped through two tight tiebreaks to put out the powerful Max Mirnyi 7-6, 7-6 and will play 11th seed David Ferrer in the next round.
Ninth seed Thomas Johansson of Sweden disposed of Juan Ignacio Chela 7-6, 6-3 in his second round match and now meets another Argentine, David Nalbandian.
