U.S. Amateur champion Matt Kuchar's success in his first U.S. Open has been one of the best feel-good stories of the week, but the boisterous behavior of his caddie/father, Peter Kuchar, also has been the talk of the Olympic Club, especially among the players.

Justin Leonard, who played with Kuchar during the first two rounds, obviously was perturbed about Peter Kuchar's exuberant celebrations. A television replay showed Leonard shaking his head in dismay on the 15th green Friday after Matt had chipped in for birdie there and his father began jumping up and down. Leonard also had to step back from a putt at the 18th because Peter Kuchar was obstructing his sightline to the hole.

This morning, before Kuchar teed off, a USGA official confirmed that his father had been asked to tone down his reactions. That was not a problem, especially on the back nine, when his son soared to a 76 and is at 5-over 215.

Leonard wouldn't publicly criticize Peter Kuchar on Friday, but today sources said Leonard had politely spoken to him about toning down the act after Leonard played with Matt Kuchar during the Masters. During the U.S. Amateur, won by Kuchar last August at Cog Hill in Chicago, several players also complained about Peter Kuchar. But the elder Kuchar is making no apologies.

"I'm hitting every shot with him," said Kuchar, a life insurance salesman. "Trust me, every shot. . . . He's pretty confident, and I mean that in a nice kind of way. It's his 20th birthday on Sunday and it's Father's Day, too. We didn't want to be on the airplane if he'd missed the cut."

Said Matt Kuchar: "Having my dad caddie has been great for me. I don't know if he would be good for other guys. I don't know if it would be an advantage for another guy to have my dad. But it's been really good for me. He keeps me calm, and seeing him get excited is just a lot of fun for both of us, a lot of fun for me to watch him."

Ernie Els, who also played with Kuchar and Leonard in the first two rounds here, said he admired young Matt's game and didn't seem at all perturbed by Peter's performance.

"He's a pretty good player," Els said. "I haven't been beaten by amateurs in a long time, so all credit to him. He really kept his composure. . . . I'm happy for the guy. His father gets quite excited but Matt's pretty calm. His dad's the other side of the coin." Montgomerie Gets an Escort

Colin Montgomerie, the target of heckling during the U.S. Open and other recent major golf championships, played the third round accompanied by two San Francisco police officers. At one point, Montgomerie asked for a spectator to be removed. On the 137-yard par-3 eighth hole, Montgomerie overshot the green and landed in a back bunker. According to Reuters, a spectator said to Montgomerie: "What did you use, a driver?"

The golfer asked one of the police officers to have the spectator removed, but the officer told Montgomerie that he had no authority to eject the fan. Montgomerie later asked a tournament marshal to have the offender escorted from the grounds, but the man could not be located.

Montgomerie, who shot a 7-over-par 77 for an 11-over 221 total, declined to talk with reporters after the round. Not Exactly a Clown Costume

Apologies to the fashion police. Those were not just any old gaudy checkerboard plus-fours Payne Stewart was wearing in Friday's round -- they were cut from cloth of the Stewart tartan pattern. Still, Payne's unofficial nickname among some colleagues in the locker room: "Bozo the Golfer." CAPTION: Some players have complained about the excessive enthusiasm of Peter Kuchar, left, son Matt's caddie.