DeGrom (2-0, 1.62 ERA) allowed two hits and walked none in his third start after spending the first part of the season on the injured list. He has given up six hits, struck out 28 and issued one walk in 16⅔ innings so far this year.
“You don’t really know what to expect coming back, but last time I was able to look at some things where I felt like I was coming off mechanically and try to make those adjustments as I went through a pretty slow process of coming back,” deGrom said. “That seems to have been paid a little.”
The two-time NL Cy Young Award winner opened the game by striking out Bryson Stott looking on a 101.1 mph fastball and then allowed a soft single to Rhys Hoskins. After Alec Bohm grounded into a force play, deGrom fanned JT Realmuto on three straight sliders.
DeGrom has struck out 28 of the 56 batters he has faced this season. That 50% strikeout percentage is the highest by any pitcher through his first three starts of a season since the mound moved to its current distance in 1893, according to ESPN Stats & Information research. DeGrom held the previous high, striking out 48.6% of batters to start last season.
“He’s doing great,” Diaz said. “He can do whatever he wants with the hitters.”
With the win, deGrom improved to 9-1 in 20 career starts against the Phillies.
Pete Alonso hit an early RBI single as the NL East leaders improved to 31-9 following a loss and 10-4 in the season series with Philadelphia. Alonso leads the NL with 97 RBIs.
Diaz issued two walks in the ninth, and Philadelphia had runners on second and third when Nick Castellanos struck out swinging for the final out. It was Diaz’s 27th save of the season.
The All-Star closer became the sixth active pitcher to reach 200 saves.
“It’s awesome,” deGrom said. “He did a great job and you feel comfortable whenever he’s in the game.”
The Mets posted their MLB-best 15th shutout. It was their first 1-0 win over Philadelphia since RA Dickey pitched a one-hitter exactly 12 years ago at Citi Field.
“The star of the show was our pitching staff,” Alonso said.
Philadelphia wasted a terrific performance from Aaron Nola (8-9), who allowed four hits in eight innings. The right-hander struck out eight and walked one, but he fell to 0-3 in four starts against New York this year.
The Phillies finished with three hits.
New York jumped ahead in the first. Starling Mars singled, stole second and took third on a throwing error by Realmuto before scoring on Alonso’s soft single to right.
After Alonso’s stroke, Luis Guillorme and Jeff McNeill had back-to-back singles in the second. Nola retired 17 in a row before McNeil started the eighth with a walk.
“Going up against deGrom, you know it’s going to be low [scoring],” said Nola. “So it was just going to be a fight all night. And it was.”
The Associated Press contributed to this story.