The Dallas Keuchel on display Sunday was the version the Braves expected when they signed him to a $13 million free agent contract last month.

The left-hander showed top-of-the rotation stuff for seven innings and looked like a guy capable of starting a high-leverage playoff series.

“He’s a master on the mound,” Charlie Culberson said. “He knows what he’s doing. He knows how to pitch. I’m glad he’s on our team and we don’t have to face him.”

Despite a hiccup by Chad Sobotka, who relieved Keuchel with runners on first and second and surrendered a three-run homer to Garrett Cooper, the Braves hung on to beat the Marlins 4-3 and win the series.

The ninth inning wasn’t without drama. The Marlins loaded with bases against Luke Jackson with no one out, a series that included an infield hit that was reversed on appeal and a bunt that bounced over the mound where there were no defenders.

The game-saving play came when Neil Walker hit a shallow fly to left, which defensive sub Culberson caught and fired a strike to Brian McCann to nail Jorge Alfaro at the plate for a double play. Marlins manager Don Mattingly argued in vain that McCann had blocked the plate.

After walking pinch-hitter Curtis Granderson to re-load the bases, Jackson retired Miguel Rojas on a fly to center field to end the game. Jackson earned his 14th save.

“That was a very athletic play by Charlie,” Keuchel said. “Nothing he does ceases to amaze me.”

Keuchel (2-2) consistently got the Marlins to hit the ball on the ground. In 7 1/3 innings, he retired 13 batters on grounders, five on flies and struck out four. He set down 13 straight at one point. He allowed five hits and one walk.

“That’s who he is,” said Josh Donaldson, who adeptly fielded seven grounds at third base. “He gets ground balls, works quick. He worked a quick first inning (six pitches) … it was awesome. You know you’re going to be on your toes, you’re going to get action.”

Manager Brian Snitker and Keuchel talked during the seventh inning and there was no question the pitcher was going back to the mound in the eighth.

“He looked like he’d just showed up. He wasn’t sweating,” Snitker said. “He told me he was just getting started. You know, he’s one of the breed that when he takes the ball, he wants to give it back to you when the 27th out was made.”

Keuchel appeared to have all of his pitches working on Sunday, even though he didn’t need to use his changeup or slider early in the game. He deemed it his best outing of the year.

“I feel like I’m in midseason form,” he said. “It took a few starts to build up. Major league starts are easy to control outside a major league game. I knew it would take a few games to get adjusted and it took some patience, but I think I’m there.”

Keuchel got offensive support early. Donaldson capped a three-run outburst in the third inning when he hit his 200th career homer, a two-run shot that landed well into the stands in right-center field. Donaldson became the 38th active player to reach the milestone.

The inning started when Ronald Acuna Jr. walked -– extending his on-base streak to 17 consecutive games --, advanced to second on Dansby Swanson’s grounder to third and scored when Freddie Freeman looped an opposite-field single to left.

The Braves had a chance to break the game open in the fourth inning when they loaded the bases with one out. But Swanson hit a sharp grounder that shortstop Miguel Rojas turned into a double play that ended the inning.

The Braves tacked on a run in the fifth when Donaldson placed a fly to right field that dropped just fair in front of three Marlins and hustled to second base for a double. Nick Markakis got him home on a looping single to left field.

Markakis had a three-hit day, increased his average to .286, and stole his first base of the season. That put the finishing touch on a 10-for-24 (.416) homestand.

The Braves are 54-37 at the break and lead the N.L. East by six games. The 54 wins are the seventh most in franchise history before the break. The team is 8-0-1 in its last nine series and improved to 10-2 against the Marlins.