WASHINGTON -- Since his big league career began in 2010, Danny Espinosa has been a regular second baseman, seen action as a reserve at third and left field, been benched and performed through an injury before taking over as an everyday shortstop this year.

Earlier this year, some Nationals fans howled for top prospect Trea Turner to be called up from Triple-A and take over at shortstop due to Espinosa's low batting average and propensity for striking out.

That talk most likely ceased Thursday evening, as Espinosa hit a grand slam in the third inning as right-handed batter and then hit a three-run shot from the left side of the plate in the fourth as the Washington Nationals crushed three homers to beat the hapless Cincinnati Reds 13-4.

"It was timely, much needed," Washington manager Dusty Baker said. "That is quite a feat. You don't see that very often. That is quite a night -- a month (of production) for some guys. He has been playing lights out. We are all happy for him."

Espinosa had a career-high seven RBIs -- plus curtain calls after each of his multi-run homers that landed among the Reds' beleaguered relievers in the bullpen beyond the left field wall.

"I had never done it in the big leagues," Espinosa said of going deep from both sides of the plate in the same game. "It feels awesome to help the team out. I kept with my work and I kept grinding and hoped that the results would show up. I was trying to have good at-bats."

Espinosa finished with nine homers in June, giving him 15 this season -- just one fewer than teammate and reigning National League MVP Bryce Harper. Espinosa entered the game hitting .213 with runners in scoring position, but he has hit better than .340 over the past 21 games.

"I have all of my teammates believing in me," he said. "It means a lot as a player."

Espinosa is batting .235 with 41 RBIs -- third on the team to Harper (46), who got the night off, and Wilson Ramos (44).

"He has persevered," Baker said of Espinosa. "He loves to play."

"It was a fun sight to see," said Gio Gonzalez, the starting and winning pitcher for the Nationals. "No one gave up on Danny. Here he comes; he is a force to be reckoned with."

It was a rough night for the Reds and starter Brandon Finnegan, who gave up the grand slam to Espinosa and allowed eight runs in 2 1/3 innings.

"It was a combination of walks and homers," Reds manager Bryan Price said. "They don't work well together. He didn't have more than one pitch he could go to. Brandon has been one of our best competitors in our rotation. He just didn't have it today."

Finnegan (3-7) gave up five hits, including two homers, and five walks.

"I couldn't command my fastball; they weren't swinging at the slider," the lefty said. "I gave them their runs. I need to throw strikes."

Espinosa became the first player in Montreal/Washington franchise history to hit a homer from each side of the plate since Geoff Blum did it for the Expos in 2001. Espinosa is the first person in franchise history to pull off the feat in which one of the homers was a grand slam.

It was the second night in a row that a middle infielder had two homers for the Nationals, as second baseman Daniel Murphy did so Wednesday against the New York Mets. Ryan Zimmerman added two hits, including a homer, and three RBIs on Thursday, and Chris Heisey had two hits and two RBIs.

The Reds scored three runs in the sixth as Joey Votto (two hits) led off with a homer, Adam Duvall had a run-scoring groundout and Tucker Barnhart added an RBI single to cut the margin to 13-4.

Gonzalez (4-7) allowed four runs on six hits with nine strikeouts in six innings. Washington had lost the previous seven starts by Gonzalez, who was 0-6 in that stretch.

"It is a step in the right direction," Gonzalez said. "I located better; all three of my pitches were working."

The Nationals (48-32) won their fifth game in a row while the Reds (29-51) lost for the eighth time in the past nine games. Cincinnati has been outscored 69-31 during that stretch.

Brandon Phillips also had two hits for the Reds, who began a 10-game road trip in rough fashion.

NOTES: Reds CF Billy Hamilton was in the starting lineup after a ball hit him in the face on Wednesday on Cubs 1B Anthony Rizzo's inside-the-park homer. ... RF Bryce Harper did not play with Washington facing against Cincinnati LHP Brandon Finnegan. Harper played in 76 of the Nationals' first 79 games. "It's that time of the year," Nationals manager Dusty Baker said. "We're halfway (through the season). So today is the day." ... Reds RHP Anthony DeSclafani (2-0, 1.52 ERA) faces Nationals RHP Tanner Roark (7-5, 2.96) on Friday. ... Reds OF Jay Bruce greeted Nationals coach Chris Speier near the batting cage before the game. Speier is a former coach with the Reds under Baker. ... Nationals RHP Blake Treinen, a native of Kansas, turned 28 Thursday.