SAN DIEGO (AP) -- Tim Hudson needed 27 pitches to get through the first inning and made a mistake against Matt Kemp that the slugger launched 409 feet over the fence in right-center.
Kemp hit a two-run homer to help the San Diego Padres beat the World Series champion San Francisco Giants 4-2 Monday night and extend their winning streak to a season-high five games.
Kemp's drive off the 40-year-old Hudson into the sandy play area at Petco Park in the third inning was his fourth homer in seven games and 10th overall. It also gave the outfielder 700 career RBIs. Alexi Amarista was aboard on a walk.
"The fastball to Kemp was a fastball-sinker I was trying to get away from him and it came back more middle," Hudson said. "He put a good swing on it to give them the lead.
"I wasn't quite as sharp as I would have liked to have been, especially with my fastball command," the pitcher added. "But I felt pretty good. It was a little bit of a muggy night out there with all the rain that came through. It's something you're really not used to here in San Diego."
Kemp had a strong second half for the Los Angeles Dodgers last season and appears to be heating up when the Padres desperately need it. They've underperformed despite general manager A.J. Preller's dramatic winter roster makeover, including the centerpiece deal to acquire Kemp from the rival Dodgers.
The slugger also homered Friday night against Colorado, and the Padres have hit six in three games since the All-Star break.
Ian Kennedy (5-9) pitched six strong innings to snap a four-start losing streak and end the Giants' six-game winning streak. Craig Kimbrel threw a perfect ninth on four pitches for his 26th save in 27 chances.
San Diego has won 13 of 18 against the Giants at Petco Park since 2013.
The Padres' previous longest winning streak was four games from June 2-6. Then they lost five of their next eight, costing manager Bud Black his job on June 15. Bench coach Dave Roberts managed one game before the Padres brought in Pat Murphy as interim manager.
Kemp's homer gave San Diego a 2-1 lead. The Giants tied it on Buster Posey's two-out single in the fifth. Kennedy retired the first two batters before allowing three straight singles, including Posey's base hit to left.
San Diego went ahead 3-2 in the fifth, when it twice loaded the bases but scored only one run. Hudson failed to get an out, loading the bases on singles by Yangervis Solarte and Alexi Amarista, and a walk to Kemp. Yusmeiro Petit came on and allowed Jedd Gyorko's go-ahead sacrifice fly.
Melvin Upton Jr. tripled leading off the sixth and scored on Solarte's third single.
Gregor Blanco homered leading off the third to give the Giants a 1-0 lead. His shot bounced off the top of the right-field wall and caromed over the Jack Daniel's party deck and into the seats. It was his third.
Hudson (5-8) came off the disabled list to make the start. He had been sidelined by a strained right shoulder since late June. He allowed three runs and five hits in four-plus innings, struck out three and walked four.
"He was off," Giants manager Bruce Bochy said. "It was pretty evident in the early going. He was battling his command and trying to get on track. He was not sharp. I don't know if it was rusty, but it's been a while since he's been out there."
Giants: Bochy said RHP Tim Lincecum received cortisone shots in both hips to treat a degenerative condition. Bochy said the affliction is common in athletes, and Lincecum will rest for four or five days. It is not considered a career-threatening injury.
Padres: LF Justin Upton wasn't in the lineup due to a strained muscle in his side that forced him out of Sunday's game, which was rained out. Assistant general manager Josh Stein said Upton is feeling better but still has some tightness. He's day to day. ... The Padres began a new policy of having Stein or assistant GM Fred Uhlman Jr. give daily medical updates rather than Murphy.
Giants: RHP Chris Heston, a 27-year-old rookie, is scheduled to start the middle game of the series. He's 1-1 with a 5.63 ERA in three career starts against San Diego.
Padres: RHP Odrisamer Despaigne (3-6, 4.64) has gone 0-2 in seven starts since his last victory, 7-1 against Pittsburgh on May 31. The Padres have lost his last three starts and six of seven.