MADRID, Oct 22: Argentina's David Nalbandian set up a semi-final battle against heavy serving Croatian Ivan Ljubicic after overwhelming American Taylor Dent 7-6 (7/4), 6-3 Friday at the 2.425-million-euro Madrid Masters.

In contrast to the 27 aces Ljubicic rained down in his earlier upset of seventh seed Joachim Johansson, the game of Nalbandian, the fourth seed, was decidedly more gentle.

Nalbandian managed four against Dent, supplemented by 35 winners and two breaks of serve. The Argentine was competing in his third quarter-final in his last four tournaments dating to the US Open.

Crowd-pleasing heavyweights Andre Agassi and Marat Safin were due for night-time quarter-final matches at the Rockodromo. Agassi, the second seed, will have it all to play for as the 2002 winner aims to eliminate the last Spaniard standing in Tommy Roberdo, seeded eighth.

Safin, the number three seed, faces underdog Luis Horna of Peru, who is trying to defeat a seed for the third consecutive round after dispatching holder Juan Carlos Ferrero and Andrei Pavel.

Ljubicic, 29th in the world, has Masters Series semi-final experience to call upon from Hamburg last spring. The 25-year-old who spent part of his childhood in a Bosnian war zone has little to fear, he said, because he feels he can produce a challenge to every opponent.

The Johansson-Ljubicic, battle, which lasted a gruelling two hours, 41 minutes, was completed without a single break of serve. There were only three break points in the serving slugfest.

Ljubicic never gave up the fight as he put the first blemishes on the record of the 11th-ranked Johansson, who came in without the loss of a set. The Croatian struck 52 winners and notched a final ace to yield three match points. A fourth double of the afternoon off the Johansson racket spelled the end.

Johansson's output in the duel was slightly better, with 56 winners and 15 unforced errors.

Thursday's results:

Marat Safin (Russia) bt Stefan Koubek (Austria) 6-3 6-3; Andre Agassi (U.S.) bt Vincent Spadea (U.S.) 6-1 6-3

Quarterfinals:

David Nalbandian (Argentina) bt Taylor Dent (U.S.) 7-6 (7-4) 6-3; Ivan Ljubicic (Croatia) bt Joachim Johansson (Sweden) 7-6 (7-2) 6-7 (1-7) 7-6 (7-3).

SHARAPOVA WINS

ZURICH: Wimbledon champion Maria Sharapova beat former world number one Venus Williams 6-3 6-4 on Friday to reach the semifinals of the $1.3 million Zurich Challenge event.

Sharapova, seeded fourth in Zurich, will now take on third seed Elena Dementieva in an all-Russian semifinal. Dementieva advanced to the last four earlier on Friday with a 6-1 5-7 7-5 win over Japanese ninth seed Ai Sugiyama.

Quarterfinal results:

Maria Sharapova (Russia) bt Venus Williams (U.S.) 6-3 6-4; Elena Dementieva (Russia) bt Ai Sugiyama (Japan) 6-1 5-7 7-5. -Agencies