ST. LOUIS -- Though starter Jonathon Niese lasted only 21 pitches before an achy left knee forced him to the clubhouse, the Mets, behind a pair of early home runs and an exhaustive effort from the bullpen, nabbed a 7-4 victory over the Cardinals on Tuesday night at Busch Stadium. The win cut into the Cardinals' advantage over New York for the second National League Wild Card spot, too. The Mets' deficit in that race now sits at 3 1/2 games.
"They know they're playing for something," Mets manager Terry Collins said. "Each and every night, we've got to grind it out."
Wilmer Flores, a non-traditional choice for the cleanup spot, crushed a three-run homer off Cardinals starter Jaime García in the first to set the tone in the series opener. Garcia, who opened his subpar night with a leadoff walk, never got much sharper. Two-out RBI hits by José Reyes and Asdrúbal Cabrera broke a tie in the second, and Justin Ruggiano tattooed a fastball for a home run in the fourth, Garcia's final inning of work. Reyes, Cabrera, Yoenis Céspedes and Flores, the Mets' 1-4 hitters, combined for nine hits, five runs scored and five RBIs.

"Today was just an overall struggle," said Garcia, who tied his season high with six runs allowed. "I wasn't able to keep the ball down. I wasn't able to get ahead in the count. It was one of those days where I was battling down there and didn't have a good feeling."
• Garcia undone by mechanical issues
Garcia's stay on the mound, though, far exceeded Niese's. Despite no hint of knee discomfort when he warmed up, Niese made it through four first-inning batters before he had to exit. In that time, he allowed one hit and walked two, setting up the Cardinals' three-run first.
Behind him, however, the Mets' bullpen covered 8 2/3 innings while allowing one run. Robert Gsellman opened that run with 3 2/3 scoreless innings to cap his Major League debut with his first career win. 
"It's not like we had ugly play; it was just a rough start," said Cardinals manager Mike Matheny, whose club fell to 28-34 at home. "If we're kicking balls all over the place, not making plays, that's one thing. That's the kind of baseball we haven't seen here lately. But you're going to have those days where you have those starts where you have to try and pick your starter up."
MOMENTS THAT MATTERED
Slugging specialists: Far more dangerous against left-handed pitching, Flores wasted no time vindicating Collins' decision to slot him cleanup when he crushed a three-run homer off Garcia in the first. Three innings later, another lefty masher took his turn when Ruggiano blasted a projected 461-foot solo shot, the longest by a Met in the Statcast™ era. More >

Ambushed:Yadier Molina gave Gsellman no time to settle in, as he jumped on the first pitch of Gsellman's big league career and drove it to deep center for an RBI double. The hit helped the Cardinals answer the Mets' three-run first with a three-run frame of their own. Molina, who leads all Major League catchers with 28 doubles this season, tallied his third- and seventh-inning singles on the first pitches of those at-bats, too.

Niese's knee: Though the Mets were aware heading into the night that Niese's left knee was a concern, he felt strong enough during his pregame bullpen session to head to the mound. It didn't end well. Niese faced four batters, allowing three of them to reach base, before departing due to knee discomfort. Gsellman relieved him, allowing two inherited runners to score before settling down to pitch 3 2/3 shutout innings in his big league debut. Niese was placed on the DL after the game. More >
"It was my first time ever coming out of the bullpen, so it felt kind of awkward," Gsellman said. "But you still have to take the mound the same way [as] when you're starting. I just thought like I was starting the game again all over again, and tried to make some pitches."

Gone streaking: A pair of streaks were extended as the Cardinals fought to get back in the game. With his sixth-inning solo shot, Randal Grichuk bumped the team's home run streak to 12 consecutive games. That's five shy of the Cardinals' season high set back in July. As far as personal streaks go, reliever Alex Reyes, who threw 2 1/3 innings, remains unscored upon since making his Major League debut. With the help of Zach Duke, who induced an inning-ending double play to strand Reyes' runner at third in the seventh, Reyes has now covered 9 1/3 scoreless innings.
"I feel like I've been throwing the ball well, just commanding the ball and keeping the ball down and executing the pitches that I have to," Reyes said.

QUOTABLE
"I think I lead the league in MRIs on this thing." -- Niese, on his knee
"I've hit Niese pretty well, so I had a good game plan, and I was prepared pretty well. Unfortunately, [I] didn't get to see him and had two at-bats off a guy I've never seen before. [Josh] Smoker, I'd never seen before, and [Addison] Reed I'd seen once. So [it was a] pretty tough night to have a game plan." -- Grichuk, on how Niese's early departure affected the offense's game planning
SOUND SMART WITH YOUR FRIENDS
Gsellman's 3 2/3 innings marked the longest scoreless relief outing ever by a Mets pitcher in his big league debut, according to the Elias Sports Bureau.

WHAT'S NEXT
Mets: With their rotation in turmoil, the Mets desperately need a strong start from their most consistent starter, Jacob deGrom. He'll start Wednesday's 8:15 p.m. ET game at Busch Stadium.
Cardinals:Carlos Martínez is seeking some positive personal momentum as he comes off one of the best starts of his young career. He'll start against the Mets for the fourth time in his career -- and second time this season -- when he takes the mound on Wednesday at 7:15 p.m. CT.
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