SCOTTSDALE, Ariz. (AP) _ Barry Bonds' hot spring start wasn't enough for the San Francisco Giants in their exhibition opener Friday against the San Diego Padres.

Bonds went 2-for-2 with two RBIs and hit his first home run of the spring, a towering drive off winter workout partner Dan Serafini. But the Padres beat the Giants 13-12, scoring four times in the last two innings.

"We just laughed at each other," Bonds said. "We're just having a good time out there, that's all. He's a good pitcher. We helped each other in the batting cage and we've worked out together. It's a long spring training, a long year. One day doesn't make or break you."

Serafini, like Bonds an alumnus of Serra High School in San Mateo, Calif., went 1 2-3 innings and allowed five runs and three hits in his Padres debut. He was acquired from the Chicago Cubs in exchange for outfielder Brandon Pernell last December.

Serafini also walked three and hit the Giants' Armando Rios in the right elbow with a pitch. Rios was lifted for a pinch runner but his elbow felt fine and he didn't expect to miss any time.

Trailing 11-9, the Padres went in front with a three-run eighth inning. Jed Hansen hit an RBI single and David Newhan then hit a go-ahead two-run single off loser Dave Maurer.

Gary Matthews Jr. added an RBI single in the ninth, allowing Eric Moody to withstand a solo shot by Doug Clark in the bottom of the inning and pick up the save.

Bobby Estalella and Chris Magruder also hit solo homers for San Francisco.

San Francisco starter Livan Hernandez, who will be the Giants' opening day pitcher, was roughed up in his initial outing. He went three innings and allowed five runs and six hits, including Ruben Rivera's solo shot.

Rivera finished 3-for-3 with an RBI and three runs scored. Tony Gwynn, who signed an option for the 2001 season Thursday night, went 1-for-3 with two RBIs. Damian Jackson had three hits in four at bats, scoring twice and adding an RBI.