ROME -- When little Michael Chang hits more aces than big Pete Sampras, you know it's not the No. 1 player's day.
Chang defeated Sampras 6-2, 7-6 (8-6) Thursday in the third round of the Italian Open, ending Chapter One in Sampras' latest adventure on clay courts.
Chapter Two begins May 25 when Sampras bids for the French Open title, the only Grand Slam he has not won. The task won't be easy judging by his final performance on the red clay of the Foro Italico.
After getting by in his first two matches of the tournament, he made too many unforced errors -- 37 to only 13 by Chang -- and could not depend on his favorite weapon -- his serve -- to pull out the match against the No. 15 seed.
"I got off to a bad start," said Sampras, who had his serve broken in the opening game. "By the middle of the second set I felt good, got a good rhythm. But the difference was he played the important points better."
Chang is no slouch on clay. He won the French Open in 1989.
But he is coming back from a knee injury that sidelined him for two tournaments this year and at 5-foot-9 he never has been a match in the serving department with the 6-1 Sampras. The top-ranked player is consistently one of the game's big hitters and many of his serves Thursday were clocked at more than 120 mph.
Chang had 11 aces to only five for Sampras, a statistic no one could recall before in their match ups.
Sampras said Chang was helped by what he called the tournament's "light balls" -- a notion dismissed by Chang. Still, Sampras did give Chang credit for stepping up his serve in recent years.
"Three or four years ago he realized he needed a weapon and worked hard on his serve," Sampras said. "In today's game, you need a weapon. That was the key to the match."
Chang said he didn't expect to win many matches with the serve but he welcomed winning "some free points" with the weapon.
The packed center-court crowd of 10,000 got on Sampras at times, expecting more from the top seed. "Where's No. 1?" a man yelled when Sampras ended an exchange by hitting a volley into the net.
"It's an unbelievable crowd," Sampras said. "Here they expect me to play great tennis just because of who I am."
Meanwhile, No. 3 Marcelo Rios beat Thomas Muster 6-3, 6-1.
Rios has dropped only 11 games in three tournament matches. He never was in trouble against Muster, who used to dominate on clay. The Austrian has won the Italian Open three times and won the French Open in 1995.
Rios briefly overtook Sampras as No. 1 this year, then slipped back when sidelined by a left elbow injury.
Defending French Open titlist Gustavo Kuerten defeated unseeded German Tommy Haas 6-4, 6-2, but Yevgeny Kafelnikov, who won at Roland Garros in 1996, was beaten by No. 11 Richard Krajicek, 6-2, 3-6, 7-6 (8-6).
Brett Steven upset No. 14 seed Carlos Moya 7-5, 6-0, and No. 12 Alberto Berasategui downed Bohdan Ulihrach 7-6 (7-3), 4-6, 6-2.