Rafael Nadal beat Roger Federer 7-5 in an exhibition match yesterday to warm up for the upcoming BNP Paribas Open in Indian Wells, California.

Joining Nadal, the No. 1 player in the world, and Federer, who is No. 2, at the Clash of the Champions were Maria Sharapova and Victoria Azarenka, who also played a match at the University of Oregon's new US$227 million basketball arena. All are Nike-sponsored athletes.

The foursome then played a set of mixed doubles.

The Matthew Knight Arena was built with the financial backing of Nike co-founder and University of Oregon Ducks supporter Phil Knight.

"We've had many big battles over the years and also had some wonderful moments in exhibition play," Federer said of his many matches against Nadal. "We've played in some amazing places and this is obviously very special doing it for Nike in a place that means a lot to Phil. We're very happy to be here tonight."

John McEnroe was a surprise guest at the event.

Knight contributed US$100 million to establish the University of Oregon Legacy Fund, which the school used to back the state bonds it needed to pay for construction of the arena, named after Knight's son who died in a scuba diving accident in El Salvador in 2004 at age 34.

Tickets for the event sold out in an hour the day they went on sale and yesterday, 12,220 packed the arena and gave the players a rock star's welcome as they entered the arena floor under a spot light and to deafening applause.

"Walking down those stairs and hearing the crowd, you would think it is normal but it is not normal for us," said Federer, 29, who has 16 grand slam singles titles.

The crowd was given a surprise in return when McEnroe appeared to randomly walk out of a tunnel onto the court during pregame introductions.

McEnroe took over the umpire's chair for the mixed doubles match, with former Oregon quarterbacks Joey Harrington and Dennis Dixon as guest sideline judges.

"I never thought I'd stoop this low," said McEnroe, who had many infamous disputes with chair umps throughout his storied career.

With Sharapova and Federer leading 5-3, McEnroe and Federer switched places and McEnroe joined Sharapova on the court and thrilled the crowd with some of his old magic, getting the team to match point before Federer came back to polish off a 6-3 victory with an ace.

Azarenka and Sharapova opened the night with an entertaining singles set that featured plenty of banter with courtside fans and each other before Azarenka won 5-4 (5-0) in a tiebreaker.

In the men's singles set, Nadal and Federer showed little of the intensity that typically when the two meet. Instead, they playfully worked their way through the set with trick shots and amusing commentary before Nadal won.

Serena Williams was originally scheduled to play in the exhibition but had to withdraw because of injury. She was replaced by Azarenka.

Williams, a 13-time Grand Slam champion, hasn't played an official match since winning Wimbledon last July because of a foot injury she sustained off the court. She had a further setback when she was diagnosed recently with a pulmonary embolism, a blood clot in her lungs. She also needed emergency treatment for a hematoma last week.