shock defeat by unseeded Tomas Behrend.

Behrend, 24, who was born in Brazil but now lives in Germany and has dual nationality, ground out a 7-5, 7-6 win over the Austrian in a gruelling match at Coral Beach.

The result was no shock to Behrend, who said afterwards he relished playing against left-hander Koubek.

"Actually I have now played three times against Stefan and I have beaten him three times,'' said Behrend. "But I knew it would be a tough match because as a player you never like to lose several times against the same opponent.'' Behrend beat 22-year-old Koubek once in a tournament in Germany, also by a 7-5, 7-6 score, and then, earlier this year, in a three-set battle in Naples, 3-6, 6-3, 6-0.

In the last eight, Behrend will meet Nicolas Massu of Chile, who yesterday eliminated Ville Liukko of Finland 6-4, 6-2.

Clay court specialist Koubek, ranked 88 in the world, came off worse in a war of attrition fought from the baselines.

Behrend, at six feet, four inches, the taller man by seven inches, was the more inclined to make the occasional foray to the net, but it was mainly a case of both men slugging it out from the back of the court.

The seed was in trouble from the moment his serve was broken in the first game and he showed signs of discomfort in the blazing hot sunshine.

During change-overs, the fair-skinned Koubek twice chose to spend his two-minute break standing in the small shaded area at the southern end of court seven, rather than sit in his chair in the sun.

Left-hander Koubek broke back in the sixth game to tie the set at 3-3 in a game of excruciatingly long rallies.

But a scorching backhand passing shot down the line sealed another break for Behrend and a 6-5 lead and then he served out confidently to win the set.

Koubek started the second set in more determined fashion and when he broke the Behrend serve to take a 4-2 lead, it seemed the match would go into a third set.

But Behrend fought back to earn a tiebreaker, which he finally won 8-6 after saving two break points.

It landed there: Number two seed Stefan Koubek makes a point to the umpire during his surprise defeat by Tomas Behrend.