Kim Clijsters began her farewell appearance at the Sony Ericsson Open by sweeping the last dozen games to overwhelm Akiko Morigami 4-6, 6-0, 6-0 on Friday in the second round.

Men's second seed Rafael Nadal, champion last weekend in California, struggled in the opening set but moved up a gear in the second to beat Brazil's Riccado Mello 7-6 6-2.

Eighth seed James Blake, who needed treatment for a wrist injury, was upset 7-6 2-6 6-3 by Frenchman Florent Serra but his Davis Cup team mate Andy Roddick beat Martin Vassallo Arguello of Argentina, 6-3, 6-2.

"The wind was changing all the time," Nadal told reporters.

"It was very, very difficult for me. But I arriving here with big confidence after playing very good tennis at Indian Wells."

Clijsters, the 23-year-old women's 2005 champion from Belgium, is due to retire later this season following her July marriage to American basketball player Brian Lynch.

The fourth seed needed a set to find her feet before ripping past the 63rd-ranked Japanese, finishing with a forehand winner.

Fellow Belgian Justine Henin, seeded second, survived a shaky start to defeat American Vania King 6-4 6-1.

Henin, who captured titles in Dubai and Doha last month, acknowledged a lack of match fitness against the world number 78.

"I wasn't at my best, far from that," Henin told reporters.

"They were tough conditions, pretty windy and hot and I needed a little bit of time to get used to the conditions.

"The second set was much better but I need to improve. I need some matches."

There were wins for seventh seed Jelena Jankovic, who beat China's Peng Shuai 6-2, 6-4, Russian Dinara Safina, a 6-1, 6-1 winner over Laura Granville, and Li Na, who put out Tamira Paszek 6-2, 6-0.

HEWITT WITHDRAWAL

Blake fired an ace to save a match point, then took treatment for a wrist injury late in his struggle with Serra.

Returning to action, the American produced another ace to hold in the penultimate game before number 64 Serra served out the upset.

"I didn't play very well, it was another bad day," Blake told reporters. "I'll try and put it behind me."

Blake beat Serra just days ago at the Pacific Life Open but has not gone past the third round of an event for nearly two months.

Australian Open finalist Fernando Gonzalez, the number five seed, defeated Swede Thomas Johansson 7-5, 6-3 and 10th-seeded Serb Novak Djokovic, last week's Pacific Life Open finalist against Nadal, beat Daniele Bracciali 7-6, 6-4.

A back injury forced Lleyton Hewitt to withdraw shortly before his scheduled match with Dutchman Raemon Sluiter.

"I'm disappointed but my back has not come up as well as I would have liked from last week, which is frustrating for me," he told reporters.

The Australian former world number one hurt his back during his second-round defeat by Serb Janko Tipsarevic at the Pacific Life Open less than a fortnight ago.