The young starters the Mets were hoping would fortify their rotation are finally pitching up to expectations.

It’s just a little late.

After David Peterson tossed seven shutout innings against the Marlins in a game that was suspended in the ninth inning due to rain, Tylor Megill threw a career-high 7 ⅓ innings and held Philadelphia scoreless into the eighth, as the Mets beat the Phillies, 4-3, in the first game of Saturday’s doubleheader against the Phillies at Citi Field.

The Mets won the nightcap, 11-4, on the strength of two Francisco Alvarez home runs, including a grand slam.

Philadelphia, who began the series locked into the top wild card spot in the National League.

Megill didn’t allow a hit until J.T. Realmuto’s single with two outs in the fourth.

Pete Alonso got a scare in the second when he got drilled in the helmet by a pitch from Philadelphia’s Taijuan Walker in the bottom of the second.

The 84-mph cutter broke the flap off of Alonso’s helmet and he stayed in the game after a visit from the training staff and Buck Showalter.

It was the 21st time Alonso had been hit by a pitch this season, the second-most in the majors behind only Seattle’s Ty France, who’s been drilled 34 times. 

Walker played for the Mets and Alonso the previous two years before signing with the Phillies last offseason. 

After Megill was pulled with two on and one out in the eighth, Brooks Raley gave up an RBI single to Edmundo Sosa, but recovered to strike out Bryce Harper.

Adam Ottavino gave up two runs in the ninth with a leadoff walk to Realmuto, a run-scoring ground rule double to Brandon Marsh and an RBI single by Weston Wilson.

With Wilson on third, Ottavino struck out Jake Cave and got Christian Pache to fly out to end it.