Melbourne, Australia ? Top-ranked Andy Roddick and defending champion Andre Agassi breezed into the third round of the Australian Open by winning in straight sets Wednesday over Czech rivals.

Agassi had a 6-0, 6-2, 6-4 win over 18-year-old Tomas Berdych, closing with an ace in 1 hour 22 minutes. Roddick fired 20 aces and didn’t lose a point on his first serve in the third set of a 6-2, 6-2, 6-3 win over Bohdan Ulihrach.

Roddick set up triple match point with a curling forehand winner down the line and finished it in 1:13 with a booming first-serve winner.

Justine Henin-Hardenne, ranked No. 1 and winner at Wimbledon and the U.S. Open in 2003, had a 6-1, 6-4 win over childhood friend Camille Pin of France in her second-round match, and fourth-seeded Amelie Mauresmo advanced in straight sets. Mauresmo has lost only three games in two matches and spent less than 90 minutes on court.

The 33-year-old Agassi, an eight-time Grand Slam winner, hasn’t dropped a set in the tournament. He converted six of eight break point chances and didn’t concede one.

Agassi took the first set in 18 minutes and Berdych did not win a game for 27 minutes, until he held serve for the first time in five attempts to close the gap to 2-1 in the second set.

“Today felt really good. I think there was a lot of quality ball striking going on, from both sides,” said Agassi, who has won his last 23 matches at Melbourne Park.

The former No. 1 had never played the young Czech, making it hard to formulate a game plan to counter his youth and speed.

“It’s hard,” he said. “I prefer playing anybody in their late 20s or on,” Agassi said.

Berdych had more winners than Agassi, 27-23, and had more aces, 12-7, but was much more inconsistent, committing 35 unforced errors to just 10 for Agassi.

Agassi next plays Sweden’s Thomas Enqvist, a 7-5, 4-6, 6-3, 6-4 winner over Slovakian Karol Beck.

Roddick moved into a showdown with fellow American Taylor Dent, seeded 27th, who overcame Juan Ignacio Chela of Argentina, 3-6, 6-4, 4-6, 7-6 (4), 7-5, in 3:30.

Dent, frustrated after mixing 83 winners with 77 unforced errors, stood behind the baseline and screamed “Yeah” to punctuate his match when Chela netted a backhand volley on match point.

Roddick said Dent was on the verge of making it in the big time and “it’s a big match for me.”

“He’s got everything. He can break serve, he can serve big,” Roddick said. “I think it’s just a matter of it coming together for him … hopefully he’ll delay it for a couple more days.”

Frenchman Nicolas Escude, winner at Doha earlier this month, had a 6-3 7-6 (4), 6-4 win over Robin Soderling to extend his stretch to seven matches without dropping a set since his return this month from a hip problem that has sidelined him since Wimbledon.

In other men’s matches, 16th-seeded Sjeng Schalken beat David Ferrer in four sets, Austria’s Jurgen Melzer beat Spaniard Galo Blanco in three and American Todd Martin — who rallied from two sets down to win in the first round — outslugged Ivo Karlovic, 7-6 (4), 7-6 (4), 7-6 (7).

Sebastien Grosjean, seeded ninth, had a 6-4, 6-3, 6-2 win over American Jan-Michael Gambill; James Blake beat Nicolas Lapentti, 6-3, 7-6 (4), 2-6, 6-1; and three-time French Open champion Gustavo Kuerten had a 7-5, 6-7 (5), 6-4, 6-3 win over Ivan Ljubicic.