Medlen allowed four hits over 7 1/3 scoreless innings to win his fourth straight start, leading the Braves to a 2-1 win over the San Diego Padres on Saturday night.
The first-place Braves increased their lead over second-place Washington to 11 games. Any combination of four Braves wins or Nationals losses will give Atlanta its first division title since 2005.
Medlen (14-12) has enjoyed a strong resurgence after a slow start. He went 1-6 over the first two months of the season but is 8-2 in his last 10 games.
In 2012, Medlen moved into the rotation on July 31 and then was 9-0 with a 0.97 ERA in 12 starts.
"Whether I'm a second-half guy or whatever it is, I just feel like I've clicked," Medlen said.
The Braves led 2-0 before Chase Headley hit a ninth-inning homer off closer Craig Kimbrel, who then pitched around a two-out walk to Ronny Cedeno for his career-best 47th save -- the most in the majors.
Freddie Freeman had three hits, including a sixth-inning homer off Robbie Erlin (2-3), to help the Braves earn their first win of the season over the Padres. San Diego won the first four games of the season series.
Medlen's surge has been especially important after staff leader Tim Hudson broke his right ankle on July 25 and was lost for the season.
Is Medlen, the staff leader in wins, the Braves' emerging ace?
"I think there are a lot of guys you could say that about," manager Fredi Gonzalez said. "I think his last four starts have been really, really good. Maybe more than that."
Medlen looked like an ace to Padres manager Bud Black.
"He's their guy," Black said. "He's won 14 games. Obviously, they're on their way to the playoffs. I suspect that he'll be their first-game pitcher."
Kimbrel overcame Headley's leadoff homer in the ninth. After striking out Kyle Blanks and Tommy Medica, Kimbrel walked Cedeno. After pinch-runner Reymond Fuentes stole second base, Nick Hundley grounded out to end the game.
"We were one base hit from tying that game," Black said. "We were right there with them."
Erlin allowed two runs on eight hits and one walk in six innings.
The Braves were denied a chance to extend their lead in the fifth when Elliot Johnson hit a two-out single and stole second. Upton singled to right field and Johnson, trying to score from second, was thrown out on right fielder Chris Denorfia's one-hop throw to the plate.
The Braves left the bases loaded in the seventh. Right-hander Dale Thayer, the Padres' third pitcher of the inning, struck out Evan Gattis to end the threat after Brad Boxberger and Tommy Layne combined to walk three batters.
San Diego's problems with walks continued in the eighth. With two outs, Andrelton Simmons doubled off Brad Brach, who then walked B.J. Upton and pinch-hitter Joey Terdoslavich. Brach struck out Elliot Johnson to end the inning.
There was a brief delay in the fifth inning when Medlen fouled a ball that hit home plate umpire Tom Hallion under his mask. The ball skimmed off catcher Nick Hundley's helmet before hitting Hallion, who remained in the game after being checked by Braves assistant trainer Jim Lovell.
Venable made a diving catch of Elliot Johnson's sinking liner in left-center in the first inning.
Gonzalez said Braves OF Jason Heyward, who took batting practice for the second straight day, could be sent to the Braves' Instructional League in Florida next week. Heyward's right jaw was fractured when hit by a pitch from the Mets' Jonathon Niese on Aug. 21. ... B.J. Upton drew three walks. ... Braves RHP Brandon Beachy (inflammation right elbow) will begin light throwing on Monday or Tuesday. ... Teheran will try for his 13th win against Padres RHP Burch Smith on Sunday.