As tough as losses are, the Mets’ 10-7 loss in the series finale against the Phillies on Sunday was as deflating as they come.

With a crucial opportunity in their pursuit for the postseason, as the Cubs — who currently occupy the second slot in the NL wild-card race — dropped back-to-back games to the Brewers, the Mets failed to take advantage.

Despite a handful of opportunities to maintain their 3-0 lead after the first inning or capitalize with runners in scoring position, the Mets’ usual go-to players didn’t get it done.

After the Phillies took a 10-6 lead in the seventh, Brandon Nimmo worked a 10-pitch walk before making it to third on an Amed Rosario single. Joe Panik drove Nimmo in before Jeff McNeil was robbed at the warning track in center, followed by a brutal pop out from Pete Alonso and Michael Conforto (both 1-for-5 with two strikeouts) striking out looking to end the inning.

“We’d like to bring those runs in and we didn’t do it today,” Conforto said. “There’s no sense in dwelling on it, we can’t change anything now. All we can do is look forward and show up [Monday] against the Diamondbacks. That’s it.”

Conforto had come through in the sixth with a single to center to load the bases for Wilson Ramos, after McNeil was issued a walk and Alonso singled. Ramos grounded out for one RBI and Robinson Cano hit a sacrifice fly for the other to bring the Mets within a run. But J.D. Davis popped out in foul territory to end the inning.

Two singles from Rosario and McNeil sandwiched a Jed Lowrie strikeout in the bottom of the ninth, before Alonso struck out and Conforto grounded to short to end the game.

When asked if the loss stung a little more because of the opportunity with the Cubs losing, Conforto said, “A loss is a loss.”

“We got to come back tomorrow and do a better job with the runners that we’re getting on and bringing them in and keeping more runs off the board,” Conforto said. “At the end of the day, that’s all we can do. Just move on from today and focus on tomorrow.”