CINCINNATI — Edinson Volquez’s pitches darted everywhere, a sign that he’s got a way to go yet in his comeback from elbow surgery.

Adam Dunn hit a two-run homer off Volquez, who had a rough time in his second start since his return, and the Washington Nationals beat the Cincinnati Reds 7-1 on Thursday for a split of their four-game series.

Volquez (1-1) dominated Colorado on Saturday in his return from reconstructive elbow surgery. He had control problems the second time out, walking four and giving up six runs in only 2 1-3 innings. He threw 75 pitches but only 38 strikes.

“I felt good,” Volquez said. “I just couldn’t find the strike zone, and they got some good swings on me. The only thing I can do is be ready for my next start.”

Dunn’s only hit in the series was his two-run shot in the third inning, his 23rd homer of the season. Knowing that Volquez couldn’t get his pitches in the right spots, the Nationals were able to wait for something in a good place to hit.

“He’s got great stuff,” said Dunn, a former teammate in Cincinnati. “He’s really, really, really good. But when he’s walking guys and you’re able to kind of zone him up, he’s a different pitcher. That was the only thing today, he didn’t have his command. That’s it, period. He had good stuff.”

Livan Hernandez (7-6) allowed seven hits during his second complete game, getting his first victory since June 21. He also singled home a run off Volquez.

Hernandez threw 102 pitches, didn’t walk a batter and struck out five during his third career win against Cincinnati, his fewest against an NL team. He’s 3-7 in 15 career starts against the Reds.

Every time out, the 35-year-old is trying to show that he can still be a top pitcher.

“I want to have a good year,” said Hernandez, who has both of the Nationals’ complete games. “I want to go out and prove people wrong. My friends and teammates are always (saying), ’You’re a good pitcher, you can pitch.’ But I’ve got to show some different people I’m not done. So I go out very excited. Every time I go pitch, I think of that and I think it helps me a lot.”

The Nationals won back-to-back road games for the first time since May 12-13. They’ve gone 8-26 on the road since then, an extended struggle that was wearing on them.

“We needed to put a couple together, especially against a ballclub as good as Cincinnati,” manager Jim Riggleman said. “We needed to win a couple, not win a game and take a step back. We needed to show ourselves we can play with these other teams and put a few together.”

Washington arrived in town with a slumping offense, but scored 22 runs in the last three games against a pitching staff that has been the best in the NL since June 17. Leadoff hitter Nyjer Morgan reached base four times and had a career-high three steals.

The Reds are hoping that Volquez’s return from surgery last August helps them stay in contention with St. Louis in the NL Central. They were greatly encouraged when he allowed only three hits and one run in six innings of an 8-1 win over the Rockies on Saturday, striking out nine with a fastball that regularly clocked 95 mph.

Against the Nationals, his pitches were out of control. He walked three consecutive batters in the second, then gave up a single by Hernandez. Dunn homered in the third, his only hit in an otherwise drab series against the team that traded him away in 2008 — 1 for 15 with six strikeouts. It was his 126th homer at Great American Ball Park, the most by any player.

Cristian Guzman followed with a triple off the yellow padding atop the wall in right — the umpires reviewed to make sure it wasn’t a homer and upheld the call. When Willie Harris followed with a single, manager Dusty Baker decided it was enough for Volquez.

“Edinson wasn’t sharp,” Baker said. “He was wild. He was throwing hard, but he was throwing too many pitches and he got into a high pitch count. That’s part of the (comeback) process.”

NOTES: Hernandez has both of the Nationals’ complete games. … Dunn is batting .182 career against the Reds with two homers. … Riggleman said RHP Luis Atilano will probably go on the 15-day DL. Atilano complained of a sore arm after his 8-7 loss to the Reds on Tuesday. … The Reds activated C Ramon Hernandez and sent C Corky Miller to the minors. Hernandez, who had been out with a sore knee, played 1B, giving Joey Votto a day of rest.