Karlovic ended the match against the 100th-ranked Brands with an untouchable ace sliced out wide.

On a Florida day that was atypically cold (temperatures dropped into the 50s at night), and typically windy, Karlovic never faced a break point on serve. Brands escaped the one break point opportunity he offered Karlovic in the 10th game of the first set.

"It was a close match, but I feel that on his serve I had more opportunities than him," Karlovic said. "In the tiebreakers I was a little bit more with concentration so I won." Karlovic's 26 aces came up six short of the open era record of 32 in a two-set match he set last week at the Memphis tournament.

Karlovic will face seventh-seeded James Blake in the quarterfinals.

Blake, a two-time Delray Beach finalist, earned his spot in the quarterfinal with a a 6-3, 6-1 win over Robin Haase of the Netherlands.

Third-seeded Benjamin Becker of Germany received a walkover against American Wayne Odesnik, who sprained his right ankle during his first-round match.

Becker will face unseeded Jarko Nieminen in the quarterfinals. The Finn was a 5-7, 6-1, 6-0 win over last year's finalist, Evgeny Korolev of Russia.

Fourth-seeded Frenchman Jeremy Chardy also progressed to the last eight with a 7-5, 4-6, 7-5 win over Santiago Giraldo of Colombia.

In a reprise of last year's semifinal, Chardy will take on defending champion Mardy Fish, who secured a quarterfinal berth by outlasting Mischa Zverev of Germany 6-2, 6-4.

The 73rd-ranked Fish, who recently dropped 12 kilograms (26 pounds), lost his serve twice in the second set. But he recouped both breaks immediately and then from 4-4, won the final two games.

Ernests Gulbis of Latvia also moved into the quarterfinals with a 6-1, 6-4 win over Teimuraz Gabashvili of Russia, who knocked out top seed Tommy Haas in the first round.

The 72nd-ranked Gulbis, 21, has played in 61 ATP tournaments and his best results have been reaching two semifinals. He reached the semifinals at the Memphis tournament last week, losing to American Sam Querrey.
 
Verdasco out, Venus barely survives in Mexico

In Acapulco, Mexico, top-seeded Fernando Verdaso was knocked out of the quarterfinals of the Mexican Open on Thursday by Juan Monaco, while women's No. 1 seed Venus Williams fought back from 1-5 down in the final set to survive.

Monaco, from Argentina, beat the Spaniard 7-5, 6-3.

Williams had a harder-than-expected struggle against Spanish qualifier Laura Pous Tio, finally winning 4-6, 6-3, 7-5. Pous Tios is ranked No. 399 and Williams is No. 5.

Verdasco, who beat Andy Roddick in an ATP final two weeks ago in San Jose, Calif., said he had not adjusted to clay after not having played on the surface in seven months.

"I played better than the first two days here, but I still didn't have the level I needed to beat a solid player on clay-and one who played well like Juan," Verdasco said. "There is not much more to say."

Monaco credited his serve.

"I have beaten a top-10 guy who has been playing well for several years," Monaco said. "But I can't think about it too much because tomorrow I have to start from zero."

Fernando Gonzalez of Chile rallied to beat Eduardo Schwank of Argentina 3-6, 6-3, 7-5, while third-seeded David Ferrer of Spain defeated Uruguay's Pablo Cuevas 7-5, 6-4.

"When I won the first set, the second was easier and I played with more confidence and was more aggressive," he said.

In the other quarterfinal, No. 4 Juan Carlos Ferrero beat two-time defending champion and fellow Spaniard Nicolas Almagro 6-1, 7-5, 6-2.

In the semifinals, Ferrer will play Gonzalez, and Ferrero will face Monaco.

Williams got herself into several holes with loose ground strokes and showed this is her first tournament of the season on clay-her weakest surface.

"I just thought I'm not going to give it to her. That's the first thing I thought," Williams said.

Williams, who won here last year, was cheered on by thousands of fans.

"I really have never had that kind of support, ever in my life," Williams added. "Never, never at home, never anywhere. ... Never Fed Cup, never even the Olympics. ... It was just really amazing. I thought, OK, yeah, I can do this."

In other women's quarterfinals, Polona Hercog of Slovenia beat Agnes Szavay when the Hungarian player retired because of a left thigh injury. Hercog won the first set 6-4 and Szavay was up 1-0 in the second when she stopped playing.

In the other quarterfinals, No. 5 Carla Suarez Navarro of Spain beat No. 3 Gisela Dulko of Argentina 6-1, 7-6 (4), and Edina Gallovits of Romania edged Sharon Fichman of Canada 7-5, 6-2.