NEW YORK -- No statistic better encapsulates the offensive ineptitude of the New York Mets during the Citi Field era than this: Entering Saturday, ace right-handed pitcher Matt Harvey has made 52 big league starts, 14 of which he didn't win despite allowing one run or less.

Harvey made sure it didn't become 15 of 53 on Saturday.

Harvey struck out nine in seven grinding innings when his first major league homer -- a two-run shot in the fifth inning -- gave the Mets the lead for good in a 4-2 victory over the Arizona Diamondbacks at Citi Field.

"During Harvey's starts, we haven't really helped him out too much," Mets catcher Kevin Plawecki said. "So to get that lead from the home run was definitely big."

Harvey appeared headed for another hard-luck loss or no-decision when he spotted the Diamondbacks a 2-0 lead before he even recorded an out in the first inning. Center fielder A.J. Pollock drew a leadoff walk and left fielder David Peralta followed with a two-run homer.

"At that point, I really wanted to do everything I could to keep the team within striking distance," Harvey said. "When you look up at the scoreboard and it's 2-0 and you've only faced two batters, the last thing you want to do is keep that rolling."

Diamondbacks left-hander Patrick Corbin carried a one-hit shutout into the fifth, but the Mets began storming back when first baseman Lucas Duda hit a long opposite field homer leading off the inning.

Corbin retired right fielder John Mayberry and Plawecki, but third baseman Eric Campbell kept the inning going by drawing a walk. Harvey followed by hammering Corbin's next pitch just beyond the orange line beyond the left field fence for his first homer since he was pitching for Triple-A Buffalo on April 25, 2012.

"I was swinging first pitch, no matter what," Harvey said. "Having a runner on, I just wanted to keep that streak going, keep the line moving."

Harvey was serenaded with chants of "MATT HAR-VEY" by the crowd of 36,038 as he crossed home plate and walked into the dugout, where he was mobbed by teammates. Then he sat down and waited out a replay to confirm that a fan hadn't interfered with the ball, which cleared the line before it was touched.

"When they were calling for replay, I was thinking I was going to be sitting in the dugout going back out to second base," Harvey said.

But the homer counted, and now the famously competitive Harvey has something to brag about to his hot-hitting rotation mates. Mets pitchers are now batting .178 with two homers (right-hander Noah Syndergaard homered at Citi Field on May 27) and 15 RBIs.

"'Thor' doesn't have anything over 'Bam-Bam' anymore," Mets manager Terry Collins said, referring to Syndergaard's nickname.

On the mound, the homer seemed to energize Harvey, who allowed eight base runners in the first five innings before recording his lone 1-2-3 inning in the sixth. He gave up a leadoff single in the seventh to Diamondbacks shortstop Cliff Pennington (1-for-2) but erased him by inducing Pollock to hit into an inning-ending double play.

Overall, Harvey (8-6) allowed the two runs, five hits and four walks.

"He came out of the first inning giving up a fast two runs and his makeup is that's it, that's all they're getting," Collins said. "If we score, we're going to win the game. This guy competes."

Shortstop Ruben Tejada homered leading off the sixth for the Mets (46-42), who improved to 34-5 when scoring at least four runs.

The Diamondbacks (42-44) have been limited to four runs and 11 hits while striking out 20 times in the last two games against Harvey and Syndergaard. Arizona entered the series with at least 10 hits in eight of its previous nine games, a stretch in which it went 6-3.

"There's a reason why these guys are two of the best young pitchers in baseball," Diamondbacks manager Chip Hale said.

Corbin (1-1), who was making his second start after Tommy John surgery, allowed four runs, four hits and one walk while striking out five in five-plus innings. He threw just 67 pitches, about 25 less than what Hale envisioned before the game.

"We didn't get his pitch count as high as we'd like to and I know he's not happy with that," Hale said. "He pitched beautifully early on and that's something we'll build on."

NOTES: LHP Jonathon Niese will start for the Mets on Sunday in place of LHP Steven Matz, who was placed on the disabled list Friday because of a torn left lat muscle. ... The Mets last had multiple pitchers hit homers in a season in 1997, when RHPs Armando Reynoso, Mark Clark and Rick Reed all homered. … The Diamondbacks set their rotation for after the All-Star break. LHP Robbie Ray will start Friday and be followed by RHP Jeremy Hellickson, LHP Patrick Corbin, RHP Rubby De La Rosa and RHP Chase Anderson. ... Diamondbacks CF A.J. Pollock needs a stolen base Sunday to become only the second player in team history with 20 steals before the All-Star Break. 2B Tony Womack had 38 steals before the break in 1999.