U.S. Open champion Kim Clijsters took another step toward winning consecutive Grand Slams with a 6-3, 6-3 win over Tamarine Tanasugarn in the second round of the Australian Open today in Melbourne.

Clijsters will next play No. 19 Nadia Petrova, one of the Russian women already into the third round after French Open champion Svetlana Kuznetsova and Maria Kirilenko.

On the men's side, defending champion Rafael Nadal converted five of his first six breakpoint chances in an emphatic 6-2, 6-2, 6-2 second-round win over Slovakia's Lukas Lacko.

No. 7 Andy Roddick had a 6-3, 6-4, 6-4 win over Brazilian Thomaz Bellucci and No. 11 Fernando Gonzalez of Chile, the 2007 runner-up, beat Turkey's Marsel Ilhan, 6-3, 6-4, 7-5.

The 26-year-old Clijsters won at Flushing Meadows in September in only her third tournament back from two years off the tour in which she got married and had a baby.

Despite her success in New York, Clijsters said she still had plenty to prove, to herself and the other players on the circuit.

"My attitude doesn't change because now I'm seen as one of the favorites," said the No. 15-ranked Clijsters. "To me, that doesn't mean anything."

BOXING

PACQUIAO TO FIGHT

Standing under the world's largest high-definition television, Manny Pacquiao and Joshua Clottey were all smiles yesterday for the announcement of their welterweight fight.

The March 13 bout will be the first boxing match at the $1.2 billion Cowboys Stadium in Dallas

Pacquiao (50-3-2, 38 KOs) is widely considered the best fighter, pound-for-pound, in the world. In November, he beat Miguel Cotto, who beat Clottey (35-3, 20 KOs) last summer.

COLLEGE HOOPS

BREAK FOR CALHOUN

Connecticut men's basketball coach Jim Calhoun took a medical leave yesterday for an undisclosed condition, the latest health concern for the 67-year-old Hall of Famer.

The school did not provide additional details. Calhoun had prostate cancer in 2003 and skin cancer twice, most recently in 2008.

Dr. Peter Schulman, the coach's primary-care physician, said in a statement he advised Calhoun to take time off "to address some temporary medical issues, none of which involve any previous medical conditions that he has dealt with."

Associate head coach George Blaney will run the Huskies in Calhoun's absence.