CINCINNATI -- St. Louis Cardinals right-hander Lance Lynn will be a free agent after the season, but says he doesn't consider his remaining starts as an audition for the other 29 teams.

With the non-waiver trade deadline behind him, Lynn remains focused on getting the Cardinals back to the postseason.

"I'm pitching for one team, this one to win," Lynn said. "I'm pitching for myself to do everything I can as a competitor. I don't care what other teams think. We did to win in bunches, that's the bottom line."

Lynn allowed one run on three hits through six innings and Paul DeJong hit a two-run homer, lifting the Cardinals to a 4-1 victory over the Cincinnati Reds on Saturday night at Great American Ball Park.

Lynn (10-6) made his first start since the July non-waiver trade deadline when he was rumored to possibly be leaving St. Louis. He was in control throughout, retiring 10 of the final 11 batters he faced.

"He kept the ball down, used good movement," Cardinals manager Mike Matheny said. "He was smart with his secondary pitches."

St. Louis (54-56) managed only four hits on Saturday but made the most of them to snap a two-game losing streak. DeJong became the first Cardinal to reach 15 home runs this season, giving them a much-needed early lead on Saturday.

"Usually scoring first is the goal for us," DeJong said. "It's just baseball. We need to score more consistent runs."

Joey Votto hit a solo homer for Cincinnati (45-65), which is 8-4 against the Cardinals this season.

Reds rookie right-hander Luis Castillo appeared to get stronger as the game wore on, retiring seven of eight with 93 pitches through six innings. But, he ran out of gas in the seventh when he took Kolten Wong's helmet off with a 93-mile per hour fastball before allowing a pinch-hit single to Luke Voit.

"When things aren't going well, my changeup is the pitch that I go to," Castillo said, via an interpreter. "Tonight, I was using it one time, two times, three times in a row. I left a two-seamer over the plate on the (DeJong) home run. I made a mistake and he hit it pretty good."

Kevin Shackelford replaced Castillo and the Cardinals scratched across two more runs on a bases-loaded infield single and a passed ball to make the score 4-1.

"We were opportunistic tonight," Matheny said.

Castillo (2-5) allowed four runs, three earned, with a season-high five walks and two hit batters in 6 1/3 innings.

"I thought his stuff was really good," Reds manager Bryan Price said. "His command wasn't there for him as much today. They had nine base runners via walks and hit by pitches. That kind of set the table for them."

The Cardinals' bullpen shut the door.

Tyler Lyons fanned three straight batters in the eighth. Cincinnati had the tying run at the plate in the ninth but Trevor Rosenthal got Jose Peraza to ground out, ending a nine-pitch at-bat for his eighth save.

Castillo had been among the most impressive of Cincinnati's young starters, but he had a rocky start to Saturday's game. He walked three batters and hit one but managed to strand runners in scoring position in each of the first two innings.

Votto's solo shot, his 28th homer of the season, with two outs in the first inning put the Reds ahead 1-0.

Adam Duvall followed with a triple to center on a ball that Tommy Pham nearly caught at the top of the wall. Duvall, however, was left stranded at third.

"Two bad pitches," Lynn said. "One cost me a run, the second one would have if Tommy didn't get a glove on it. Other than, everything was pretty good."

The Cardinals broke through against Castillo in the third when DeJong blasted a two-run shot to put them ahead 2-1.

"I'm just trying to have good at-bats and letting my natural power play," DeJong said. "Guys are making adjustments on me. I'm just looking for a pitch in my hot zone."

NOTES: Reds C Devin Mesoraco started for the first time since July 29 due to a sore left knee. He went 1-for-4. ... Reds SS Zack Cozart is expected to be reinstated from the disabled list and return to the lineup on Sunday. He's been on the DL since July 29 with a right quad strain. ... Cardinals CF Dexter Fowler, on the DL list with a left forearm strain, took batting practice on Saturday and could return during the current road trip. ... Reds 1B Joey Votto now has 249 career home runs. Only six players in franchise history have 250 or more.