The top-ranked Swiss star won their last encounter 6-4, 6-3 in South Korea on Tuesday, but the latest clash in Malaysia took nearly 90 minutes and proved a bit more difficult.

Their age difference became the decisive factor — at 26, Federer was never in danger of losing against an opponent a decade older who retired from competitive tennis five years ago.

Nevertheless, Sampras, who has won a record 14 Grand Slams, showcased his big serves and hit ferocious forehand returns down the line — the hallmarks of his 1990s heyday.

The pair traded point for point in both sets in Malaysia's Malawati Stadium, where Sampras had the crowd gasping at his ability to prevent Federer from steamrolling over him.

"I was impressed with Pete tonight," Federer told reporters. "He played some unbelievable shots, but then again he is capable of doing that. He had an incredible serve which was so difficult to read tonight."

Federer — who has won 12 Grand Slam titles — said he knew that Sampras would improve after their first match in Seoul "and tonight he didn't prove me wrong."

Sampras acknowledged Federer's superiority in the match.

"I am happy with my performance tonight. I hung in there right until the end," he said.

Sampras retired in 2002, a year after his only previous meeting with Federer at Wimbledon. Federer won that fourth-round match in five sets.