Former Giants prospect Zack Wheeler pitched seven sharp innings, Marlon Byrd homered again and the New York Mets completed their first sweep in San Francisco since 1994 with a 7-2 win Wednesday.
Daniel Murphy and John Buck each had two hits and drove in two runs as the Mets won their fourth in a row, including three straight over the slumping World Series champions. The Giants have lost 16 of 19.
Wheeler (3-1), a former Giants first-round draft pick, took a shutout into the seventh. He allowed one run and three hits overall, striking out five and walking three.
Matt Cain (5-6) lasted less than an inning for the first time in his career, giving up three runs on two hits while getting just two outs. He walked three.
San Francisco dropped a season-worst 10 games under .500 as it was swept at home for the first time in nearly a year.
Wheeler retired 14 of the first 16 hitters before Pablo Sandoval singled for the Giants' first hit with two outs in the fourth. Wheeler also hit an RBI double.
Cain's home ERA rose to 5.94, the second-highest among qualifying NL pitchers. He crafted a 2.03 ERA at home last year.
The Mets took a 3-0 lead in the first. Eric Young walked, stole second went to third on catcher Buster Posey's throwing error and scored on Murphy's single. Ike Davis and Kirk Nieuwenhuis drew walks ahead of Buck's two-run single, when ended Cain's day.
Giants reliever Mike Kickham retired 12 of the first 14 hitters he faced into the fifth. That ended when Davis singled ahead of Byrd's 15th homer of the year, and second in two days.
Wheeler and Murphy each doubled home a run in the sixth to make it 7-0.
Brandon Crawford singled home a run in the Giants' eighth and Tony Abreu hit a sacrifice fly in the ninth.
NOTES: Giants RHP Santiago Casilla could be activated Thursday. ... LHP Madison Bumgarner (9-5, 3.05) will start for the Giants on Thursday night in San Diego. He's 5-3 in 15 games against the Padres. ... RHP Jeremy Hefner (4-6, 3.39) gets the start for the Mets on Friday night at Pittsburgh. Since June 4, his ERA is 1.64. ... Mets INF David Wright extended his hitting streak to 11 games with a single in the top of the ninth.