The exhibition between world number one Roger Federer and US great Pete Sampras could take on added intensity Monday as Federer bids to sharpen his game heading into the Indian Wells Masters.

Federer's aura of invincibility has slipped a bit with a loss to Novak Djokovic in the Australian Open semi-finals and first-round exit in Dubai last week.

Now recovered from the mononucleosis that had slowed him, Federer will play a fourth exhibition match against the 36-year-old Sampras at storied Madison Square Garden.

Federer, 26, and Sampras met just once in competition, at Wimbledon in 2001. Then the unseeded Federer upset defending champion Sampras in five sets to reach the quarter-finals.

Last November the duo played three exhibition matches in Asia. Federer beat Sampras 6-4 6-3 in Seoul, and 7-6 (6) 7-6 (5) two days later in Kuala Lumpur. Sampras took the third match in Macau 7-6 (8) 6-4.

"We had the best time, the one week we were together in Asia traveling around," Federer said. "It was just very interesting to hit balls with Pete.

Federer said he was excited to be part of tennis' return to Madison Square Garden for the first time since 2000. The last time men's tennis was staged at the Garden was in 1996.

"I never got the chance to actually play at the Garden, but I heard so many great things," he said. "It's just something that is also maybe a goal of mine, once in my career to be able to play there.

"And there's going to be 18,000 to 19,000 people, that's even better."

Federer said 14-time Grand Slam champion Sampras still possessed some formidable weapons.

"I don't even come close to his volleys today still," he said. "It just shows, if you have a solid technique, if you feel comfortable at the net, it's something that's just very natural.

"And his serve - you can wake him up at two in the morning and he'll hit a monster serve," Federer said. "It's just no problem for him because he's got the best motion."

Although Sampras retired in 2002, Federer said the American was still able to exert plenty of pressure in a point.

"Even in (exhibitions), you've got that pressure and feeling that the other players back in the day used to feel, you know, the break point or on big points, he would come up with the big serve or he would put pressure on you and come to the net and challenge you, and that's exactly how I felt playing against him."

AFP