Jon Lester pitched 5 1/3 strong innings to help the Nationals win for the third time in four games.
Schwarber's homer was his fourth in three times. The Nationals moved him into the leadoff spot Saturday in the opener of a day-night doubleheader. He led off this game with a home run, hit two on Sunday and launched the go-ahead shot this time against reliever Clay Holmes (2-2).
"When he's swinging at balls in the zone, he is going to hit it hard somewhere," Nationals manager Dave Martinez said.
Schwarber had an RBI single in the next and walked. His only outside was a line drive caught by jumping second baseman Adam Frazier at the first inning.
Lester made it to the sixth for just the fourth time in nine starts this season. He allowed a leadoff double, then got a line-drive out before being removed. The 37-year-old left-hander is averaging 4 2/3 innings per start this season. He does not have a win however.
"At the end of the afternoon, we've got to win ballgames," Lester said. "I don't care how we can do it."
Wander Suero replaced him allowed a gentle single and Erik Gonzalez's sacrifice fly that tied it at two.
Schwarber pushed Victor Robles house with his single from the next. Juan Soto's only drove Trea Turner to give the Nationals a 2-1 lead later in the inning.
"When our offense starts clicking, and we start scoring runs, we'll start consistently winning games," Martinez said.
Kevin Newman opened the scoring with his second homer of the year to give the Pirates a 1-0 lead at the second.
Washington ace Max Scherzer is among eight players on the MLBPA executive committee and also one of just two association player representatives. Therefore, when he speaks on a wide subject, his words carry weight outside his Hall of Fame pitching résumé.
He had been asked Monday about Major League Baseball's anticipated crackdown on pitchers utilizing the"sticky stuff" to boost their grip, and, occasionally, spin rates, when throwing the baseball.
"There is answers to all people and how we proceed forward with this and that which are the rules of what the practice should be," Scherzer said. "And specifically, what hitters want. I believe that is the biggest question: What do hitters want? We've heard from plenty of hitters. All the hitters that talk openly, they want the pitchers to have a tack within the baseball, a clasp over the baseball. So what that looks like, that's a conversation we'll have."
Scherzer also said he knew as much about baseball prospective enforcement as reporters did, meaning MLB isn't communication with the union about it.
"Whatever has been written is that which we know," Scherzer said. "There hasn't been additional information besides that."
Pirates: RHP Trevor Cahill was placed on the 10-day injured list Saturday because of a left calf injury, two weeks after being reinstated in the IL. He drove just 1 1/3 innings in his start Thursday. Pittsburgh director Derek Shelton reported the Pirates will take their time bringing the veteran pitcher back next time. "I think we'll look at several approaches to take care of it, whether it's different modalities or spans of time, and just continue to proceed on that path and determine how we can get him back healthy," Shelton said.
Nationals: Scherzer threw a bullpen however it did not go as well as he hoped. He threw 10 pitches and his groin wouldn't loosen up, so that he will not make his scheduled start Wednesday. The three-time Cy Young Award winner said it's up to Martinez if he belongs on the injured list or just has his flip pushed back a few days. Scherzer tweaked his groin Friday and obtained just one out. He said Sunday that he would be unable to make his next scheduled start if he could not undergo a bullpen.
Pittsburgh sends LHP Tyler Anderson (3-6, 4.52 ERA) to the mound in the middle game of this collection. Struggling LHP Patrick Corbin (3-5, 6.21) goes for the Nationals.