Second seed Kim Clijsters reached the last 16 of the Italian Open with a 4-6, 6-1, 6-3 win over Japanese qualifier Akiko Morigami on Tuesday.
The 22-year-old Belgian, the highest-ranked player in the claycourt tournament after Amelie Mauresmo withdrew with a stomach bug, struggled to find her rhythm at the start.
Clijsters made a series of unforced errors to let slip a one-break advantage and gifted Morigami the first set.
However, she steadied herself to break the Japanese in the first game of the second set after which it was no contest.
"The last time I played on clay was in Warsaw (earlier this month) and the surface was completely different," said Clijsters, who will regain the world number one ranking from Mauresmo if she wins in Rome this week.
"It took a bit of time to get used to it, but I kept going for my shots and luckily things went better in the second and third sets."
Clijsters next faces 16th seed Dinara Safina, who did just enough to beat Maria Elena Camerin 6-4 6-4.
"She's a very good player and if I want to win I will have to play good tennis," said Clijsters.
"She's young and hungry and has a good kick serve that puts a lot of pressure on the opponent. It will be important to be playing well from the start."
Most of the top players enjoyed comfortable passages into the last 16.
Last year's runner-up Patty Schnyder, seeded sixth, earned a 7-6, 6-2 victory over Vera Dushevina to set up a clash with 1999 Rome champion Venus Williams.
Fifth seeded Russian Elena Dementieva went through after her opponent Shuai Peng of China pulled out of their match injured.
Apart from Clijsters, the only seed to struggle was 2004 French Open champion Anastasia Myskina, who needed treatment for a thigh strain during the second set against Italy's Roberta Vinci before coming through 6-0, 1-6, 6-4.
"I don't want to use my leg as an excuse, but it stopped me running today," the 10th seed said.
"I played a very nervous match. I was just lucky she wasn't good enough to take advantage, but if I play like that in the next round I'll lose for sure."
