NEW YORK -- The Cardinals immediately showed the Mets how badly they want to play in the postseason on Wednesday night, and a great catch by Lars Nootbaar to rob a home run in the seventh inning made sure they would secure their 11-4 victory at Citi Field.

While the Cardinals’ offense dominated the three-game series, the defense prevented the Mets from pulling to within one run late.

Nootbaar pulled back what would've been a momentum-shifting three-run homer from Pete Alonso to end the seventh, keeping St. Louis' four-run lead intact and dealing the Mets' comeback chances a significant blow.

A scrappy rally against Cardinals lefty Andrew Miller had the Mets set up for more damage, with Alonso targeting his team-best 34th homer of the year, but Nootbaar ranged back to Citi Field's right-field nook and perfectly timed his leap to end the inning and set off a celebration from his Cards teammates.

Nootbaar thought the ball was going over the fence for a home run. But after he checked to find the wall, he looked back up and the ball wasn’t as far as he thought.

“I found my footing right by the wall and tried to do what I could,” Nootbaar said.

“Off the bat, I thought [it was out],” Mets manager Luis Rojas said. “The kid made a nice play, a very nice play. He just came into the game and was ready, so you’ve got to credit that, too.”

Nootbaar might not have made the catch if not for coach Willie McGee. Before a series on the road starts, McGee has Cardinals outfielders walk around the warning track and check out the nooks and crannies around the outfield.

“[McGee] is throwing balls against the wall just to see how it bounces off the fences,” Nootbaar said. “In that right-field area, [the ball] shoots back a little bit.”

Nootbaar said he loves that the Cardinals are great on defense. In fact, according to both The Fielding Bible and FanGraphs, the Cardinals led the Major Leagues in defensive runs saved entering Wednesday’s action.

“We take pride in our defense,” Nootbaar said. “As an organization, that goes from the Minor Leagues on up. That’s something we pride ourselves on. … For me, getting limited opportunities, it’s almost like if I’m not getting a hit, I don’t want anybody else [on the other team to get a hit as well].”

However, Nootbaar would like to be more consistent at the plate. He is 18-for-86 (.209) this season.

“The contagious bug has not hit me. I hope to get sick with that really soon,” Nootbaar quipped.

The Cardinals swept the three-game series, have won seven of their last eight games and remain ahead of the Reds and Padres for the second Wild Card spot in the National League. The Cards will welcome the Padres to Busch Stadium for a huge three-game series this weekend.

St. Louis took Mets right-hander Tylor Megill to school by batting around in a five-run first inning. It started with Tyler O’Neill, who doubled to score two runs. O’Neill later scored on a single by Dylan Carlson. Two batters later, Carlson and Edmundo Sosa scored on a single by Harrison Bader.

For starter Jon Lester, the first inning made life easier for him to pitch against the Mets.

“At the same time, we’ve seen what their lineup can do,” Lester said. "After you get a five-run lead right there, you just try to get that first guy out. Then you kind of settle in. [The Mets] had a quick first inning. It felt good to get the boys back in the dugout and get them swinging again.”

One thing Cardinals manager Mike Shildt loves is when his team “adds on” when it comes to scoring runs. After the five-run first, St. Louis tacked on six more. Paul Goldschmidt, Nolan Arenado, Bader and Sosa highlighted the scoring with solo home runs.

“It was tremendous. It was absolutely fantastic,” Shildt said. “We jumped out to an early lead, a lot of quality at-bats. We kept adding on, especially on a day like today.”

The Cardinals scored enough runs to help Lester notch his 199th career win. He pitched six innings, allowing three runs (two earned) on six hits with no walks and seven strikeouts.

“He was very good,” Shildt said. “… He gave us everything he had. He was a real pro today. He pitched with a lot of guts.”