Andres Chaparro had two hits and drove in three runs, and the Nationals dealt Reds starter Chase Burns his first loss since April 10, beating Cincinnati 8-2 Saturday night in Washington.
Abimelec Ortiz had a two-run single for the Nationals, who have won the first two games of the series.
Clayton Beeter (5-3) pitched a scoreless eighth inning to earn the win.
Burns, who was seeking to win his 13th consecutive decision, matched his season high with five earned runs allowed. He gave up six hits while walking three and striking out six.
It was only the third time this season Burns had given up more than three runs. The Reds are now 16-6 in his starts.
Washington starter Andrew Alvarez allowed a run on three hits over 5 1/3 innings.
Eugenio Suarez homered in his second straight game for Cincinnati and drew a walk.
Washington took a 2-0 lead in the third. Jose Tena led off with a single and went to third on a double by CJ Abrams. Ortiz scored both runners when he grounded a single to left.
The Reds tied it in the sixth. Sal Stewart singled with one out against Alvarez and Suarez homered to left center off Max Kranick to make it 2-2.
The Nationals regained the lead in their half of the sixth. Dylan Crews led off with a double and scored when Daylen Lile singled to left. Keibert Ruiz doubled Lile to third and Nasim Nunez walked to load the bases one out later, chasing Burns
Sam Moll replaced him and pinch hitter Chaparro blasted a double past third baseman Ke’Bryan Hayes. Two runs scored but Nunez was thrown out at home. Chaparro took third on a wild pitch and scored on Jacob Young’s single to make it 6-2.
In the eighth, Jorbit Vivas walked, stole second and scored on a two-out single by Chaparro. After Young was hit by a pitch, Chaparro scored on an Abrams’ single to push the lead to 8-2.
