WASHINGTON — Francisco Lindor was uncomfortable, to say the least, as he took an up-and-in fastball during Monday night’s sixth inning. 

The pitcher was Steve Cishek, who earlier this season drilled Lindor in the C-flap covering his mouth, leaving the Mets shortstop bloodied as he attempted to bunt. 

“Today, he hit [Starling] Marte and I was saying, ‘Please don’t hit me,’ ” Lindor said. “The first pitch was inside … I was scared. But thank God, I was able to put a good swing [on the third pitch], and the ball went out.” 

That three-run homer delivered a haymaker for the Mets in their 7-3 victory over the hapless Nationals. 

The Mets’ winning streak reached a season-high seven games on a night Max Scherzer wasn’t his sharpest but persevered for the win. The other half of the team’s dynamic duo, Jacob deGrom, is scheduled to pitch Tuesday night. DeGrom will be appearing in a regular season game for the Mets for the first time since July 7 of last year. 

Lindor said he reminded himself Cishek wasn’t trying to hit him as he dug in against the right-hander with the Mets leading 4-3 in the sixth and two runners on base. 

“I was very happy because I made it through the at-bat and, secondly, I helped the team,” said Lindor, who cleared the fence in left-center. 

“It’s one thing to be that tough mentally, to hit period, let alone to hit a ball the other way like that,” Buck Showalter said. “It was a big blow for us and it gave us a cushion after [the Nationals] had gotten back into it.” 

Lindor posted a .933 OPS in July, which tied his best full month offensively since arriving to the Mets. And so far, so good in August. 

Lindor’s 18 homers are second on the team to Alonso’s 27. Lindor extended his RBIs total to 73, a testament to players such as Brandon Nimmo and Marte getting on base ahead of him, as much as Lindor’s penchant for delivering with runners on base. 

“He’s posting up,” Showalter said. “He’s the same guy every day he walks through the door. He loves to play, loves to compete and likes it a lot when the Mets win and he’s real sincere about it.” 

Four two-strike singles in the second helped the Mets score three times to take a 3-1 lead. Alonso walked and Mark Canha singled to begin the stretch of two-strike hits. Jeff McNeil and Tomas Nido each stroked an RBI single in the inning. Marte’s single was the Mets’ fifth hit of the frame, but Nido was thrown out at the plate by Juan Soto for the third out. 

“What has impressed me and makes me the happiest is our ability to hit with two strikes,” Lindor said. “After we are done with that we come to the dugout and talk about it and help each other out.” 

Alonso smashed a solo homer in the third that extended the Mets’ lead to 4-1. The blast was Alonso’s 11th in 33 games at Nationals Park and gave him 86 RBIs this season. 

Scherzer lasted 6 ²/₃ innings and allowed three runs, two of which were earned, on six hits with five strikeouts and two walks. The win was No. 197 in Scherzer’s career. 

Scherzer scuffled in the fourth, allowing two runs that shrunk the Mets’ lead to 4-3. Soto homered leading off the inning and three straight singles on first pitches — by Yadiel Hernandez, Nelson Cruz and Luis Garcia — gave the Nationals another run. Soto’s blast might have been a parting gift to the Washington fans — it’s possible he will be dealt by Tuesday’s 6 p.m. trade deadline after last month rejecting a reported 15-year contract extension from the club worth $440 million. 

The Nationals scored an unearned run against Scherzer in the first inning. After Soto drew a two-out walk, Josh Bell doubled to right field. Marte threw to an unoccupied second base — instead of hitting the cutoff — allowing Soto to race home. Bell reached third on the play, but was left stranded.