Chair umpire Larry McMullen ought to know.

Although Sampras was playing a fun and relaxed exhibition match Sunday during the Alumni Legends Cup in Tiburon, the retired 14-time Grand Slam singles champion became annoyed when, in the seventh game of the first set, his opponent - talented 19-year-old Sam Querrey - hit a backhand down the line that a linesman ruled in. Sampras thought the shot was closer to Mill Valley than in and asked McMullen to overrule.

He didn't.

"Are you embarrassed? You should be embarrassed,"

PISTOL PETE: PEte Sampras flashes a smile as he serves against Sam Querrey in their exhibition match Sunday at the Tiburon Peninsula Club.

said Sampras, turning serious. Then Pistol Pete walked to the sideline below the umpire's chair to towel off and let off some steam.

"I don't get pissed off much, but that pissed me off," Sampras snapped at McMullen.

So there you have it. Sampras came to Tiburon to get tested and he got testy instead.

"No respect out there," Sampras joked later.

That's a shame. The Oakland Raiders, arguably the worst team in professional football, manage to attract a sellout crowd on Sundays while Sampras, arguably the greatest tennis player ever, couldn't fill the place in a tennis-mad area.

Well, they missed quite an exhibition. After that controversial call, Sampras fought off nine set points to win that game. He eventually lost the first set 6-4, but he won the next set 7-6 by winning the tiebreaker 7-2. But, in the decisive 10-point match tiebreaker, the 6-foot-6 Querrey prevailed 10-6.

"That's fun for me because there's no greater challenge for me to go out and play someone who's half my age," Sampras said. "He's (ranked) 48th in the world he's just going to get better and better. To play at that level is a big challenge for me to keep up."

In all fairness, Querrey has beaten several players in the top 25 this year (James Blake, Tommy Haas, Mikhail Youzny and Juan Monaco) and Sampras hasn't been playing or practicing regularly since he retired from competitive tennis in 2005. He's been busy golfing while raising two boys with his wife, actress Bridgette Wilson. He's not in his best tennis shape.

"I'm like an old beat-up truck," Sampras quipped.

If so, the exterior may be a tad rusty and the tires may have less tread, but the motor still has some get up and go. Sampras' serve has some sting left and his forehand still has some zip. After his exhibition singles match, he teamed with TPC pro Brandon Coupe, who recently was named assistant coach at Stanford, in a doubles match against Querrey and 24-year-old Pablo Pires de Almeida of Fairfax. Sampras and Coupe won 12-10, 10-3 in a pair of tiebreakers.

OK, so Sampras wasn't exactly Wimbledon-ready. He grunted to get to some balls and he popped up one service return that landed beyond the grandstand in a clump of trees. Consider it his mulligan for the day.

"I kind of surprise myself every now and again," Sampras said. "At the same time, I see myself missing (shots) a little more, like today. It's like I'm old now."

Old enough, albeit, to take on the undisputed king of the court, the 26-year-old Federer, the man who is two Grand Slam titles from tying Sampras' record. They will play a series of three exhibition matches five days apart, beginning on Nov. 20 in Seoul, South Korea. They're talking about doing some exhibitions in the U.S, too, after they earn what Sampras said was some "Christmas money" playing each other in Asia.

"I don't know what to expect," Sampras said. "I think initially the first couple of games I'll be like a caged lion, trying to hold my own a little bit. But I practiced with him (at Sampras' house in L.A. for two days earlier this year) and I held my own É I hope to be competitive. I don't want to embarrass myself. I want to go out and play well."

Evidently, Sampras played well enough against his opponent Sunday that Querry is ready to bet his Christmas bonus that Federer will have his hands full.

"I'd be surprised if Pete didn't take him out," said Querrey, who was living in Santa Rosa when Sampras beat Boris Becker in 1995 to win Wimbledon then beat Andre Agassi in the U.S. Open finals the same year.

That, of course, assumes that Sampras is going to start training hard and playing more than two or three times a week against some college kids.

"Mentally I'm fine," Sampras said. "Physically I'm actually OK, but tennis-wise I'm just not as sharp."

That's the main reason Sampras came to play in Tiburon, where the first Alumni Legends Cup was won by Stanford, which defeated UCLA 6-1 in the finals. Competing against Querrey in a competitive environment was a test for Sampras to gauge where he stands for the "true test" when he plays Federer.

How did Sampras grade himself Sunday?

"Seven and half," he said on a scale of 1-to-10. "If you balanced it out, the linesmen were about a two."