SAN FRANCISCO - Jason Bay and Dave Williams were quite the sight - Bay with his neck stained with grass from a diving catch, and Williams with his closely cropped mutton chops.

Their play on the field was rather noticeable, too.

Bay hit a three-run homer and Williams pitched six strong innings to improve to 2-0 since growing his funky sideburns, leading the Pittsburgh Pirates past the San Francisco Giants 5-2 Tuesday.

Jose Castillo and Humberto Cota also went deep for the suddenly powerful Pirates who have 18 home runs in May.

"The lack of home runs wasn't going to last all year," said Bay, who believes the Pirates have been more relaxed at the plate recently. "It was a matter of guys getting going."

Bay, last season's NL Rookie of the Year, hit his sixth homer of the year on a 3-1 pitch from Jim Brower (1-1) in the sixth. It gave him a nine-game hitting streak and spoiled a strong spot start by Jeff Fassero.

"That was a big home run for us," said Lloyd McClendon, who earned his 295th victory to move into a tie with Gene Lamont for 10th on the team's all-time managerial list. "We don't get many three-run homers. At this point in the season, it was really big for us, especially on the road. That will usually spell victory for you."

Bay also made an impressive diving catch in center field on a hard-hit line drive by Pedro Feliz in the fourth.

Castillo led off the seventh with his second homer. Cota added a solo shot in the ninth.

Jose Mesa worked the ninth for his 12th save this year and 22nd straight dating to last season. That is one off the club record set by Mike Williams from Sept. 3, 2000-June 28, 2001. Dave Williams (3-3) allowed two runs and five hits to win his second straight following a three-start losing streak and avenge a loss to the Giants on April 30.

He tried to match Fassero.

"I figured he was in the pen to start the year and I didn't know how long he'd go," Williams said. "I wanted to keep the same rhythm."