The Mets already had the lead, and lefty-hitting Michael Conforto was walking to the plate to face a left-handed pitcher. Now if the game had been tied or if the Mets had trailed, chances are Conforto’s view would have been from the bench, not the batter’s box.

But this was the spot and the time for Mets manager Terry Collins to stick with Conforto. And Conforto rewarded the confidence with a two-run single in the Mets’ four-run seventh during their 7-2 home-opening wipeout of the Phillies on Friday at Citi Field. One inning earlier, Conforto drove in a run the conventional way, victimizing a righty for a double. His three RBIs matched his career high.

“Great feeling obviously,” Conforto said of his lefty-lefty matchup success, noting the more important aspect was “helping the team put runs on the board [to] give us a little extra cushion. In that situation, I just wanted to hit the ball hard somewhere and wasn’t really thinking too much about the matchup. That’s the key to having success in those situations, so it felt good, yeah.”

But had the score not been tilting toward the Mets already, Collins would have summoned Juan Lagares.

“We made a decision when we face left-handed starters that Juan’s going to play because Juan has good numbers against left-handers. This was a particular situation in the game where I thought [Conforto] could hit,” Collins said. “Had we not scored more runs, we were going to double switch in that spot anyway and get Juan in the game. So he and Lucas [Duda] both are going to face some lefties.”

So Conforto, who has a pair of World Series homers to his credit, had a big impact on the home opener, going 2-for-3 (with a hit by pitch) with a run scored and the three RBIs.

“It was a great experience. Obviously it’s good to be back in New York, and it started off the right way with a win,” Conforto said. “It is a little bit backwards, but I’m happy to be here with this team again.”

And figure it will be for a long while. Against righties and lefties.

“He’s a fast learner,” Collins said. “He’s going to be a very, very good hitter. He’s going to hit homers, he’s going to drive in runs. Right now, we kind of like the platooning thing, but Michael Conforto is going to be a good player in this league for a long time.”