SAN FRANCISCO — Jered Weaver had hoped to get his season back on track after stumbling through his first five starts.
It took just four pitches to remind the Los Angeles Angels' opening-day starter that he still has a long way to go.
Weaver gave up back-to-back home runs to San Francisco's first two hitters and the Angels never recovered in a 5-0 loss to the Giants on Sunday that completed a three-game sweep.
"It's weird, I have no answers," Weaver said. "Basically I'm serving BP up there right now. What are you going to do? I've got to work with what I've got."
Weaver (0-4) gave up five runs and 10 hits in five innings. The three-time All-Star is 0-5 with a 6.25 ERA since beating Texas on Sept. 20.
Nori Aoki hit his first home run of the season on Weaver's first pitch of the afternoon. Three pitches later, Joe Panik homered on a hanging curve. It's the first time the Giants opened a game with consecutive home runs since Chuck Hiller and Duke Snider did it against Bob Gibson and St. Louis on May 27, 1964, according to STATS.
Angel Pagan came within 15 feet of making it three straight when he tripled off the brick wall in right-center, not far from where Panik's home run landed.
"Just when you think everything is going to go good ... it starts out like it did today," Weaver said. "Just got to figure a way to dig myself out of this."
Los Angeles manager Mike Scioscia said Weaver's problems are stemming from his fastball, which averaged 84 mph in April, down from 86-88 mph last year.
"No doubt his velocity has ticked off from where it was at the end of last year," Scioscia said. "His margin of error is not usually what it is because of where his stuff is right now. It doesn't mean he's not going to be successful."
Tim Lincecum pitched three-hit ball over eight innings for the Giants. San Francisco has won eight of 11 following a 4-10 start.
Lincecum (2-2) walked one and struck out four in eight scoreless innings, lowering his ERA to 2.40. The two-time NL Cy Young Award winner also singled twice off Weaver.
"He did it all today," Giants manager Bruce Bochy said. "Just a terrific job. His fastball command really can determine how his game goes."
Lincecum allowed only three runners in the first five innings then pitched out of two-on, no-outs jam in the sixth.
San Francisco made it 3-0 in the third when Panik singled and scored as Brandon Belt hit into a forceout.
Brandon Crawford hit a two-run, two-out double in the fifth.
Angels: C Chris Iannetta, who sustained a cut finger on his throwing hand a week ago, singled in the sixth to end an 0-for-21 slide. ... Iannetta was batting in the ninth spot. Manager Mike Scioscia had Weaver batting eighth — the first time in franchise history that a starting pitcher has batted eighth.
Giants: RHP Matt Cain (flexor tendon strain) will continue to throw off flat ground for the next week. ... RHP Jake Peavey (back strain) will throw a bullpen session Tuesday. ... OF Hunter Pence (fractured forearm) took batting practice before the game for the first time since getting hurt.
Angels: RHP Matt Shoemaker (2-1) starts Monday in Seattle and has not lost in five career games against the Mariners.
Giants: LHP Madison Bumgarner (2-1) faces San Diego on Monday looking to redeem himself after giving up five runs and 10 hits in just three innings against the Padres on April 11.