Top seed Rafael Nadal [Images] produced another irresistible display of high-energy tennis to battle his way to a 7-6, 6-4 victory over Radek Stepanek and claim a place in the semifinals of the Madrid Masters on Friday.

The 19-year-old world number two had to be at his very best to see off the feisty Czech, but with his characteristic mixture of aggression and athleticism he won through to the delight of the capacity crowd at the Madrid Arena.

"Stepanek was a very uncomfortable opponent and it was a very tough match," said Nadal. "But the important thing is that I'm in the semis in front of my home crowd.

"I haven't played well in Madrid in previous years and I really want to make the final this time."

Nadal will now meet powerful American Robby Ginepri who produced an immaculate exhibition of controlled power tennis to beat Spain's David Ferrer 6-1, 6-4.

They will be joined by the in-form Croatian Ivan Ljubicic who fought his way from a set down to clinch a 4-6, 7-6, 6-4 victory over Chile's Fernando Gonzalez and extend his winning streak to 15 matches.

Ljubicic, who has won back-to-back tournaments in Metz and Vienna, will face Argentine David Nalbandian, the man he lost to in the semifinal last year in Madrid.

Nalbandian, seeded five, tamed the big-serving Ivo Karlovic with some devastating returns to claim a richly deserved 6-4, 7-6 victory over the giant Croatian qualifier.

The 23-year-old Nalbandian, a quarter-finalist at Wimbledon and in the Australian and U.S. Opens, became only the second man to break the Karlovic serve on his way to the first set.

He was unable to repeat the trick in the second, but forced a tie-break and gained the crucial advantage when he beat Karlovic at the net with a heavily spun backhand cross court before going on to serve out for the victory.

CAUGHT COLD

Nadal was caught cold by Stepanek at the start of his match when the Czech broke serve in the opening game, but the Mallorcan soon began to find his rhythm and hit back with a break in the fourth.

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He earned himself a set point in the 10th game, but the determined Stepanek, who disposed of Tim Henman and Jose Acasuso in earlier rounds, fired off an ace to level at 5-5.

With the two players matching each other blow for blow the set boiled down to a tie break.

Nadal was seemingly coasting at 6-2, but Stepanek battled on to save six more set points although it was not enough to stop the Spaniard edging a thrilling tie-break 11-9.

Nadal kept up the pressure in the second set and earned himself the crucial break in the ninth game with three superb passing shots and a devastating return of service.

Earlier a highly focused Ginepri made an impressive start against Ferrer rattling through the first set 6-1.

The 23-year-old 16th seed, who lost to Andre Agassi [Images] in five sets in the semi-final of this year's U.S. Open, showed no signs of weakness on his own serve and always had Ferrer under pressure on his.

"I came out playing extremely well," said Ginepri. "I served well, got off to a good start and David wasn't on the top of his game at the beginning.

Gonzalez became the first man to break Ljubicic's serve this week and end the Croatian's 81-game service winning streak when he broke in the seventh game on his way to taking the opening set.

But Ljubicic turned the tide after trailing by a break to take the second set after a tie-break 7-2.

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