Tyler Stephenson and Nick Castellanos hit consecutive home runs, Kyle Farmer broke open the game with a grand slam and the Cincinnati Reds kept alive their slim playoff hopes by routing the Washington Nationals 9-2 Sunday.

Cincinnati won its third straight and is six games behind St. Louis for the second NL wild card with six games left, tied with Philadelphia.

At 81-75, the Reds ensured consecutive non-losing seasons for the first time since 2012 and '13.

"All these games are important," Reds manager David Bell said. "We are focused on each day to finish strong."

Tyler Mahle (13-6) allowed one unearned run and three hits in six innings as the Reds won a third straight game and won a series for the first time since a four-game sweep of Miami from Aug. 19-22. They had dropped eight straight series before splitting two games against Pittsburgh.

Mahle's strikeout of Nationals' pitcher Josh Rogers was his 200th of the season, extending his career high.

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"What is most meaningful to me is that I made all my starts and pitched more innings than I have in awhile," Mahle said. "That is what allowed me to reach 200 strikeouts"

NL batting leader Juan Soto of Washington went 0 for 3, dropping his average to .322.

Rogers (2-1), pitching in front of hundreds of family members and friends from his Louisville, Ky.-area hometown of New Albany, Ind., gave up three runs, seven hits and a season-high four walks in 4 2/3 innings, his fifth start since Tommy John surgery.

"He struggled with his location," manager Dave Martinez said. "His fastball command was off today. He battled. He gave up two home runs but still kept us close. It was just one of those days. He couldn’t find the strike zone consistently. He couldn’t keep it down."

Stephenson finished a triple short of hitting for the cycle.

"I didn’t think about the cycle until (TJ) Friedl said something to me, but someone would have to break a leg in the outfield for me to get a triple," Stephenson said.

India misplayed Lane Thomas' grounder, allowing the ball to bounce off his body and into right field for a run-scoring error in the fifth.

India doubled leading off the botton half, Stephenson hit an opposite-field homer to right and Castellanos followed with his career-best 32nd, a drive to left-center field, Castellanos has homered in three straight games.

"That’s the mentality there," Bell said. "India makes an error but come backs to hit the double. That’s his competitive nature. He wants to make every play, but when he doesn’t, he wants to make the next play."

Farmer made it 7-1 in the sixth against Ryne Harper with his career slam.

"It’s unfortunate," Harper said. "I felt like I threw some good pitches. One pitch will do ya. Wish I could have it back. When you get into that situation, it’s important that you attack. You want to throw your best pitch. I executed most of my pitches that inning. There was one that I didn’t."

NOT HAPPY

Eugenio Suárez used his foot to cover the plate with dirt to protest being called out on strikes to end the third inning.

ABOUT TIME

Asdrubal Cabrera singled in the fifth inning for his first hit as a Red. He’d been 0 for 20 since being claimed off waivers from Arizona on Aug. 27. Rogers threw the ball to the visitors’ dugout, but plate umpire Ángel Hernández motioned for the Nationals’ batboy to throw it to the Reds’ dugout.

WELCOME, DAURI

RHP Dauri Moreta made his major league debut in relief of Mahle in the seventh inning. Moreta finished with a walk and a strikeout in one inning.

TRAINER'S ROOM

Reds: LHP Amir Garrett felt discomfort while pitching in the eighth inning. After talking with an athletic trainer and throwing a couple of warmup pitches, he got the inning’s final out.

UP NEXT

Nationals: RHP Josiah Gray (1-2), Monday’s scheduled starter at Colorado, allowed two runs in six innings of his first career start on Wednesday at Miami.

Reds: LHP Reiver Sanmartin will be called up from Triple-A Louisville to make his major league debut starting in place of injured LHP Wade Miley for Cincinnati’s game on Monday against the Pirates, which was postponed from Wednesday.