Maine pitched into the eighth inning and Delgado hit his first home run of the year, leading New York over the punchless Colorado Rockies 6-1 on Monday night.
"Big fella got the first one under his belt," Mets manager Willie Randolph said. "There will be many more to come."
Jose Valentin had a three-run homer and four RBI, while Moises Alou went 3-for-3 with a walk and two runs to help the Mets rebound after losing two of three to division rival Atlanta at home last weekend.
"It's a good sign that we forget about the past. You move on," Valentin said. "It's fun to be in a lineup like this."
Matt Holliday had his third consecutive three-hit game for Colorado, which has lost 14 of 15 at Shea Stadium. Once known as the Blake Street Bombers, the Rockies have not homered in six straight games, matching a franchise record that was accomplished twice in 2002.
"We've got guys who have driven the ball in the past -- and we will again," said Colorado manager Clint Hurdle, at a loss to explain the power outage. "It's slowing things down. The consistency is what we are lacking, one big knock to loosen things up."
Playing their first game outside the NL West, the Rockies (8-12) lost for the fourth time in five overall. They have only seven homers all season, fewest in the major leagues.
"We've got a lot of good hitters. We get a couple guys going and it'll be contagious," Holliday said.
After taking a no-hit bid into the seventh inning during his previous outing Wednesday at Florida, Maine (3-0) allowed seven hits in 7 2/3 innings to lower his ERA to 1.71. He has lasted at least seven innings in three of his four starts.
"I've been working hard on conditioning, things like that, and it's paid off," Maine said. "My goal coming into the season was going out there and pitching at least six innings each time out there. I had a tough time with that last year."
The 25-year-old right-hander walked two and struck out five, including No. 8 batter Clint Barmes three times.
"It's nice to watch him," Delgado said. "He's one of the key components of this ballclub. If he does good, we're going to do well. And he's been a big difference from last year. He's a little bit more mature, he's a little bit more under control."
"I think I've done three strikeouts one time -- never four," said Barmes, who stared silently into his locker for several minutes after the game. "We just haven't been knocking guys in."
Valentin connected in the second inning off Taylor Buchholz (1-1), making his first start of the year. He was moved from the bullpen to the rotation to fill in for injured Rodrigo Lopez (elbow strain).
Delgado was shaken up after getting hit on the left pinkie by Buchholz's pitch in the fifth. But in his next plate appearance, he hit a two-run shot off Bobby Keppel to make it 6-1 in the seventh.
"Hand is good, just a little sore. I kind of got lucky because he didn't get me square," Delgado said.
While Delgado broke out, David Wright remained in a bad slump. He went 0-for-3 with two strikeouts and a walk, leaving him hitless in 15 at-bats with eight K's. Wright has no homers and four RBI this year.
Maine pitched a four-hit shutout to beat Buchholz and the Houston Astros 7-0 on July 21 last season at Shea Stadium. Valentin and Delgado also homered in that game.
"I'm real proud of John," Randolph said.
Valentin's home run Monday gave him two homers and seven RBI in three career at-bats against Buchholz.
"I made two bad pitches and they really hurt. I let down (against) the bottom of the order, and you can't let that happen," Buchholz said. "They're solid one through eight -- the best in baseball."
Valentin added a sacrifice fly in the fourth to drive in Alou, who doubled off the top of the left-center fence. Alou got hung up on Shawn Green's hard comebacker, but reached third safely when Buchholz mistakenly threw to first.
"I kind of caught him out of the corner of my eye. I thought he was almost to third, so I got the sure out," Buchholz said.
Holliday leads the NL with a .400 batting average, three points ahead of Alou.
- Delgado had not homered in 118 regular-season at-bats dating to last year, the longest drought of his career.
- Alou has 10 multi-hit games this season, six in his last seven games.
- Beltran helped Maine with a couple of nice catches in deep center.
- Buchholz singled in the fifth for his second hit in 33 career at-bats.