CINCINNATI -- Jacob deGrom didn’t feel great in the bullpen prior to his start on Friday night at Great American Ball Park, but he admitted that is not unusual for him this season.

“Last year, it seemed like every time I took the ball, I felt really good,” deGrom said. “There have been a few [times] this year where I haven’t felt that great, but I’ve been able to battle through and give these guys a chance.”

He did it again against the Reds in the weekend series opener, boosting his case for a second straight National League Cy Young Award by tossing seven shutout innings, while Pete Alonso became the first Mets player to hit 50 home runs in a season as the Mets rolled to an 8-1 victory.

deGrom went seven innings for his seventh start in a row, allowing four hits with nine strikeouts and no walks. He threw 96 pitches before running out of steam.

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“To me, he just lengthened his lead in that Cy Young race with that outing tonight,” said Mets manager Mickey Callaway. “This guy’s incredible.”

The Mets’ third straight win keeps them 3 1/2 games behind the Brewers for the second National League Wild Card spot. The Mets also trail the Cubs -- who lost on Friday afternoon, 2-1, to the Cardinals -- by 1 1/2 games.

Alonso’s 50th homer was a two-run rocket in the eighth off Reds reliever Sal Romano that sailed an estimated 437 feet to the smokestacks in deep right-center field.

“He’s obviously very strong,” Romano said. “He just put a good swing on a tough pitch and hit it a long way. Says so much about how locked in he is.”

By the time Alonso clobbered his historic homer, deGrom had the game pretty much in hand. He improved to 3-1 with a 1.42 ERA in six career starts against the Reds.

deGrom has allowed one or no runs in each of his last three starts. He has walked one and struck out 28 over that span, helping the surging Mets remain in the playoff hunt.

“Recently, I’ve been able to locate all four pitches,” said deGrom, who has pitched 197 innings through 31 starts. “Just having a feel for the changeup, slider, being able to move the fastball in and out, keep guys off balance.”

Jeff McNeil hit a solo home run in the sixth to give deGrom the lead, and Amed Rosario padded it with a two-run shot in the seventh. McNeil’s homer was a towering drive that reached the home bullpen in right field. It was McNeil’s eighth home run in 23 games since returning from the injured list.

The Reds had runners in scoring position in the second, third and fourth innings, but deGrom got the final out via strikeout in each of those frames to keep the game scoreless.

“We got to see firsthand why he’s been so good,” said Reds manager David Bell of deGrom. “We just were not able to get anything going off him. He had the velocity, the cutter, the change. He had it all working.”

Reds starter Luis Castillo, meanwhile, allowed just one hit through five innings, and ultimately gave up three runs on just three hits, with seven strikeouts. But surrendering the two homers kept him from earning his 16th win.

“He had a good fastball today,” said McNeil of Castillo. “His changeup is his main pitch. That's his go-to. I got him 1-0, he threw me an inside fastball. I was ready for that changeup, I was kind of sitting on it. I was lucky enough to put a good swing on it and keep it fair."

Rosario’s two-run dinger in the seventh, his 14th, came on Castillo’s 100th pitch.

While Alonso, who now has homered in three straight games, can set his sights on the Major League rookie home run record held by the Yankees’ Aaron Judge, who hit 52 homers in 2017, he’s remaining focused on team goals.

“Right now, we’re trying to win games and trying to sneak into the playoffs,” Alonso said. “I’m just focused on tomorrow.”