SAN FRANCISCO (AP) -- It was only fitting that Buster Posey delivered another big hit on a night he was honored again.
Posey hit a tiebreaking RBI single after receiving a prestigious award before the game and the San Francisco Giants reduced their magic number for clinching the NL West to two with a 5-1 victory over the San Diego Padres on Friday.
Posey was recognized in a pregame ceremony with the ''Willie Mac'' award as the most inspirational player on the team. The 2010 NL Rookie of the Year then delivered another big hit when he drove in Marco Scutaro with a single off Casey Kelly (2-2) that gave San Francisco a 2-1 lead in the fifth inning.
''He's done that a few times this year,'' manager Bruce Bochy said. ''Tremendous player. He was honored to receive that award. What a great player he is on both sides. He's done such a great job for us. He's done all the little things.''
Posey helped Ryan Vogelsong (13-9) match his career high in wins and put the Giants in position to clinch a division title as early as Saturday. San Francisco would win the West on Saturday night with a win if the Los Angeles Dodgers lose earlier in the day to Cincinnati.
''It's in our hands,'' Bochy said. ''When you're in this situation you want to go out there and take care of business. You want to get in through the front door not the back door.''
Pablo Sandoval belted his fourth home run in three days, and Brandon Crawford and Scutaro had RBI singles as San Francisco matched a season high with its fifth straight win.
Chase Headley hit a solo shot for his 29th homer for the Padres. But he was thrown out at home trying to score the tying run on Yasmani Grandal's two-out double in the sixth. The Giants cut him down with a well-executed relay from left fielder Gregor Blanco to Crawford to Posey, who fielded the throw on a short hop and tagged Headley to preserve a 2-1 lead.
''We really didn't swing the bats very good tonight against Vogelsong,'' Padres manager Bud Black said. ''Other than Chase, we really didn't threaten them. Vogelsong did a nice job. His curveball was working tonight as was his changeup. We couldn't mount any pressure.''
Vogelsong, who had a 10.31 ERA over his past seven starts, reversed his recent slide by allowing just one run and five hits in six innings.
''I'm going to sleep for the first time in about a month tonight. I can tell you that,'' Vogelsong said. ''I'd been trying to tweak some stuff here for a while. I finally found something that felt comfortable and easy to repeat. Somehow I got twisted around there along the way. It took me a while to get back into something that felt right.''
The Giants broke it open with three runs in the sixth, capped by Sandoval's homer. After going 161 at-bats without a long ball, Sandoval has regained his power stroke this week and now has 12 homers this season.
It was a big day all around for Posey, who won the award named after Hall of Famer Willie McCovey that is voted upon annually by Giants players, coaches, training staff and the fans.
Posey also got a boost in his bid to win the batting title when teammate Melky Cabrera requested to be disqualified from the NL honor. Major League Baseball and the players' association agreed to a one-season-only change in the rule governing the individual batting, slugging and on-base percentage champions.
Serving a 50-game suspension after testing positive for testosterone, Cabrera leads the league with a .346 average. Cabrera had 501 plate appearances, one short of the required minimum if the Giants play 162 games, but would have won the title under section 10.22(a) of the Official Baseball Rules if an extra hitless at-bat were added to his average and he still finished ahead. With Friday's agreement, that provision won't apply this year to a player who ''served a drug suspension for violating the Joint Drug Program.''
Posey, who is hitting .335, trails Pittsburgh's Andrew McCutchen by three points for the NL lead with less than two weeks left in the regular season.
''Personal achievements and accomplishments are always nice,'' Posey said. ''Being fortunate enough to win a World Series in 2010 and knowing how much fun that was and this year with the guys on the team and the whole city. Ultimately that's where I get the most satisfaction.''
NOTES: Kelly allowed two runs and seven hits in 4 1-3 innings. ... Headley's 21 HRs since the All-Star break are the second-most in San Diego history, trailing the 28 by Ken Caminiti in 1996. ... The Padres reinstated closer Huston Street from the DL before the game. He had been out since Aug. 11 with a strained left calf. ... Grandal left the game in the seventh inning after taking a foul ball off his mask. ... The Giants autographed a hat for 49ers QB Alex Smith, who had been fined $15,000 last season by the NFL for sporting a Giants hat after games - though the fine was later dropped. INF Ryan Theriot also bought 49ers hats for his teammates. ... Madison Bumgarner (15-10) starts the middle game of the series on Saturday against San Diego's Andrew Werner (2-1).