Before batting practice, manager Bruce Bochy talked to his squad about finding ways to play better on the road, an issue he referred to as the "elephant in the closet."
"I do believe it's a stigma. You can believe it or you can shed it. It's your choice," he said.
Then the Giants (64-54) went out and improved to 25-34 outside San Francisco.
"His message was to let it all hang out," Rowand said. "It was a great message and a great time for that message. We're going to play to win, not play not to lose."
Pinch-hitter Nate Schierholtz chased Livan Hernandez (7-8) with a two-run double in a three-run sixth inning that broke it open. Randy Winn added three of the Giants' 18 hits, their most since compiling 18 at Dodger Stadium on Sept. 30, 2007.
It was a rare offensive outburst. San Francisco, which began the day ranked next-to-last in the majors in runs, moved within one game of idle Colorado for the NL wild-card lead.
"One thing we know, for us to have success we've got to pick it up on the road," Bochy said. "We've talked about this so many times. Keep it simple. Let's have some fun."
Rowand had a blast. A Gold Glove center fielder, he threw out a runner at the plate in the first inning and snapped an 0-for-14 slump with a single in the second.
"I found a hitch in my swing," Rowand said. "In the last week and a half I watched a lot of video to figure out what was going on. I was fouling off a lot of fastballs I should have been hitting."
Gary Sheffield had an RBI single for the Mets, still missing a slew of stars.
Third baseman David Wright, on the disabled list with a concussion, returned to Citi Field on Monday and said he felt better -- two days after he was hit flush on the helmet by a 94 mph fastball from Giants pitcher Matt Cain.
Martinez, from nearby South Orange, N.J., also had a frightening injury this year. He was hit by a line drive during his second big league appearance April 9, leaving the right-hander with a concussion and three small fractures on the right side of his head.
After a long rehab assignment, Martinez (3-1) returned to the majors Aug. 5 and moved into San Francisco's rotation. He's won twice in three starts, boosting the Giants' playoff push.
Pitching with his parents and other family members in the stands Monday night, Martinez yielded one run and five hits in five innings before being lifted for a pinch hitter.
Afterward, he was asked how many supporters he had at Citi Field.
"More than 10, but less than 100. I honestly had no clue," Martinez said. "We had a lot of people who I didn't know."
Pablo Sandoval got the Giants started with an RBI double in the third. Rowand sent a solo shot just over the left-field wall in the fourth, and Eugenio Velez tripled to open the fifth before scoring on Freddy Sanchez's sacrifice fly.
Velez added a run-scoring groundout in the sixth, making it 6-1.
The Mets announced more bad news late in the game. Alex Cora, who had been filling in for injured Jose Reyes at shortstop, will have separate operations to repair both ailing thumbs. Cora is expected to miss the rest of the season.
"We just really never got going. Never got in the game. Just one of those nights," Mets outfielder Jeff Francoeur said. "After a couple day games like that I think, just looking around, we all looked tired. Just kind of beat. I think all this stuff with David and Cora and stuff like that just kind of wears you down a little bit."
Hernandez, who pitched for the Giants from 1999-02, gave up six runs and 11 hits, which matched a season high. He has been roughed up in each of his past three starts, losing all three.
"I [felt] really good today. Better than the last two times," Hernandez said. "I got one bad inning."
Sandoval made two throwing errors at third base. ... After capping a tough at-bat with a tying double Sunday, Winn got his second consecutive start in RF for the Giants. He went 3 for 5 with a double and scored twice. ... Injured Mets CF Carlos Beltran (right knee) felt good after running in a straight line, manager Jerry Manuel said.