Giles hit a grand slam and the San Diego Padres beat New York 7-4 on Sunday to salvage a split of their four-game series.
"It was a sinker -- same pitch I thought he threw me in the second at-bat that I flew out to center on," Giles said. "I put a better swing on it this time."
Zambrano (1-2) retired the first two hitters of the fourth inning. Clay Hensley singled, Dave Roberts walked and Josh Barfield had a base hit to load the bases for Giles, who hit his fifth career grand slam.
Giles' second homer of the season came on a full-count pitch and made it 5-0 San Diego. It was his first grand slam since July 28, 2001, when he homered for the Pittsburgh Pirates.
It was a rare sight for the Padres, whose 12 home runs are last in the National League.
"We needed a big hit, we have been missing it," San Diego manager Bruce Bochy said. "He came through big time. It sure makes life easier when you get a big hit."
Barfield and Vinny Castilla each had three hits for San Diego. Barfield hit a solo home run in the first and scored three times.
"He [Barfield] is swinging the bat well and playing good defense," Bochy said. "He is a good player and is only going to get better."
Zambrano gave up five runs and seven hits in four innings. He hasn't lasted more than five innings in any of his three starts. He struck out one and walked three.
"Today, it was obviously pretty much bad game management," Mets manager Willie Randolph said of Zambrano. "He gave up an 0-2 home run [to Barfield], which is not what you want to do. He made bad pitches at the wrong time. He has to do a better job of
managing his game."
San Diego starter Hensley (1-1) worked 5 1/3 innings, allowing four runs and five hits. He walked three and struck out three in his second start this season and third of his career.
"I'm not quite where I want to be," Hensley said. "We still have a lot of work to do, a lot of conditioning. I feel that I am a little behind as far as stamina and stuff, but I think we're in the right direction."
Trevor Hoffman worked the ninth for his third save in as many opportunities.
Mike Cameron, who was traded to San Diego by the Mets, went 0-for-3 with two strikeouts and two walks in his Padres debut. Cameron was playing for the first time since suffering multiple facial fractures in a collision with then Mets teammate and center fielder Carlos Beltran while pursuing a ball in right-center on Aug. 11, 2005, in Petco Park.
"There is only one speed to play this game," Cameron said about adjusting for his return. "You need at-bats to get comfortable and obviously, I haven't gotten those. ...The swings are going to come together, it is just a matter of seeing the ball well."
The Mets scored four runs in the sixth. David Wright drove in the first run with an infield single and Cliff Floyd followed with an RBI single to right. Endy Chavez added a two-run single to center before Alan Embree struck out Kaz Matsui on a full-count pitch with the bases loaded to end the inning.
"We keep fighting back," Randolph said. "My team plays hard all the time. We don't give up."
Mets first baseman Carlos Delgado failed to homer for the only time in the series. He still went 2-for-5 with a run scored. ... The Padres activated Cameron from the 15-day disabled list before the game and optioned pitcher Jon Adkins to Triple-A Portland. ... Padres pitcher Chris Young will have an MRI on Monday resulting from a lack of feeling in his right thumb. ... Beltran did not start for the third straight game because of discomfort in his right hamstring. He is day-to-day. ...The seven runs and 12 hits were the most by the Padres at Petco Park this season.