SCOTTSDALE, Ariz. (AP) _ Barry Bonds homered twice, driving in five runs, and four other Giants also hit home runs as San Francisco rallied past the Chicago Cubs 13-5 Wednesday.

Marvin Benard added a go-ahead three-run homer in the fourth and Rich Aurilia, Bobby Estalella and Russ Davis each had solo shots as the Giants overcame a 5-0 first-inning deficit.

Bonds boosted his spring homer total to seven, six of them coming in his last eight games.

Chicago starter Jon Lieber (2-2) was shelled in a five-inning outing, giving up 10 runs on 11 hits, including four of San Francisco's six home runs. Brian Williams and Rick Aguilera gave up one homer each.

``What he got beat on today was all hard stuff, fastballs, sliders. No offspeed stuff,'' Chicago manager Don Baylor said of Lieber. ``His arm is fine.''

San Francisco closer Robb Nen, pitching for the second time in three days, had another tough outing in his ongoing comeback from offseason elbow surgery.

Starting for the first time in seven years, primarily so the Giants could see him face the heart of Chicago's order, Nen got two outs, allowed four runs and one hit. He fanned Sammy Sosa but walked the last three batters he faced, the last coming with the bases loaded.

``I felt fine out there. I just didn't throw strikes,'' Nen said. ``I'm still just trying to get mechanically right. It's going to come.''

Sosa, playing for the first time since banging a knee sliding into a base Sunday, was hitless in four at bats and fanned three times.

Winner Joe Nathan relieved Nen and was greeted by Jeff Reed's three-run triple. He walked Damon Buford and allowed an RBI single to Lieber before settling down.

He allowed one run on six hits in 5 1-3 innings with three walks and five strikeouts.

Felix Rodriguez, John Johnstone and Ben Weber finished up by pitching one scoreless inning each.

``After that first inning, the rest of the guys shut'em down. It was beautiful,'' San Francisco manager Dusty Baker said. ``Nathan was the most relaxed I've seen him this spring. He had good control. He shut down those Cubs, and those guys can hit.''