Tomas Berdych caused a surprise with a straight-sets win over world number two Rafael Nadal to reach the semi-finals of the Madrid Masters.
Berdych is enjoying a good run of form in Madrid
The 21-year-old Czech number one silenced the partisan crowd with a 6-3 7-6 victory for his third consecutive win over the Spaniard.
He will play Chile's Fernando Gonzalez in the last four after the 10th seed beat Serb Novak Djokovic 7-5 5-7 7-5.
David Nalbandian meets world number one Roger Federer in the other semi-final.
Berdych was in superb form, holding his serve with confidence and then taking his opportunities to break his opponent.
I can play better and have been with every round of the tournament
The 21-year-old, who beat sixth-seed Andy Roddick on his way to the quarters, looked on target for another win when he eased his way to the first set.
The 10,000 strong crowd got behind Nadal in the second set, but Berdych kept his cool to keep up the pressure and win through after a nail-biting tie-break.
Berdych left the court to jeers after putting his finger to his lips in a silencing motion.
"I can understand they want him to win the match and the tournament, but this is not a Davis Cup where you can expect this - not in this tournament," said trhe Czech.
Nadal responded: "When I played him in the Czech Republic, the crowd was the same and I didn't say anything.
"If you play against a local player, that's normal, that's good for tennis because the public supports you."
I'm very proud to have walked off the court 80 times as a winner and only five as a loser - it means a lot
Argentine Nalbandian, who put out Britain's Tim Henman in the previous round, had to battle all the way before beating Marat Safin 6-4 6-7 (6-8) 7-6 (7-2).
Top seed Federer saw off a spirited challenge from American Robby Ginepri 6-3 7-6 (7-4) for his 17th consecutive victory - his 80th of the year.
Nalbandian broke serve early in the first set but was pegged back three times in the second, with Safin taking his fourth set point in the tie-break.
Safin broke in game 11 of the decider and served for the match but Nalbandian levelled and dominated the tie-break.
It is the third straight year that Nalbandian has reached the last four in Madrid.
"I pushed very hard, and it wasn't the best way to do it, but I'm happy with the win," he said after seeing off Safin.
"I can play better and have been with every round of the tournament. But the semi-final will be tough."
Despite being edged out, Safin said he was "more happy than frustrated" because of his recent good run of form.
"I've been playing some great matches," the Russian said.
"Before the US Open I was 104th, now I'm fighting for the Top 30.
"I've made all these points in the last four-and-a-half months and I hope I can be seeded in the Australian Open."