SAN FRANCISCO Marlon Byrd's two-out grand slam capped a five-run eighth inning as the New York Mets beat the Giants 10-6 Tuesday night.
The Mets squandered leads of 3-2 and 5-3 but held off the slumping World Series champions by scoring five times against their bullpen.
Omar Quintanilla had three hits for the Mets, while Byrd and David Wright added two apiece. Wright drew a two-out walk before Byrd's home run off reliever Jake Dunning.
The Giants lost their third straight game, seventh of eight and 18th of 23.
Marco Scutaro singled twice for the Giants but was thrown out at home trying to score from first base on Pablo Sandoval's double in the first.
The Giants scored more than four runs for just the fourth time in 22 games but still lost and fell a season-high nine games under .500. San Francisco also has the worst record in the majors (17-34) since May 13.
Scott Rice (4-5) retired one batter for the win as the Mets overcame a shaky outing by starter Dillon Gee.
Carlos Torres pitched the final two innings and gave up Nick Noonan's pinch-hit RBI single in the ninth, one night after New York's bullpen tossed nine scoreless innings.
San Francisco's bullpen was also stellar in the extra-inning game Monday but couldn't follow suit this time after the Giants scored single runs in three straight innings to tie the score 5-5.
Giants starter Barry Zito allowed seven hits and five runs in six innings. He remained winless in his last seven starts dating to May 30.