Santana (4-0) overcame a rain delay of 1 hour, 7 minutes in the third inning and outlasted Cubs right-hander Jeff Samardzija, who had his long winless streak continue. Samardzija lowered his ERA to 1.45, second in the NL, but he is still without a win this season.
Santana walked one and struck out seven. Samardzija allowed only two hits with one walk and seven strikeouts in six innings.
Braves left fielder Justin Upton is day to day with a lower back muscle bruise after being hit by a pitch from Samardzija in the sixth and leaving the game.
Braves closer Craig Kimbrel pitched the ninth for his 10th save.
Kimbrel, who blew a 2-1 lead in the ninth in the Braves’ 3-2 win in 10 innings on Friday night, was back in form. He walked Starlin Castro with two outs before striking out Luis Valbuena to end the game.
The Braves scored two runs in the seventh off right-hander Brian Schlitter (2-1). Following singles by Chris Johnson and Andrelton Simmons, Doumit pinch hit for Santana and drove in Johnson with his double. Simmons scored on Tyler Pastornicky’s suicide squeeze bunt.
After being hit by the pitch from Samardzija, Upton ran to first base but, after being checked by Braves trainer Jeff Lovell, walked slowly off the field in apparent pain.
Upton had another injury scare in the fourth inning. He appeared to hurt his lower back when he tagged Anthony Rizzo at the end of a long run-down between first and second. Upton ran in from the outfield to help on the play. Rizzo collided with Upton, who then bent over and reached for his lower back but remained in the game.
The run-down play helped keep the Cubs from scoring following a leadoff single by Ryan Kalish.
As Kalish advanced to third on Rizzo’s single, the throw from right fielder Jason Heyward was headed toward third base and Rizzo tried to advance to second. Simmons cut off Heyward’s throw, starting the run-down play.
Kalish was stranded on third base as Castro hit a fly to shallow right field, Valbuena walked and Wellington Castillo struck out.
The Cubs also left a runner at third base in the second inning. Castro led off the inning with a double but Santana retired the next three batters.
Samardzija’s winless streak was extended to 13 starts. His last victory came on Aug. 24, 2013, at San Diego.
NOTES: The Braves placed RHP Jordan Walden on the 15-day DL, retroactive to May 5, with a strained left hamstring. LHP Ian Thomas was recalled from Triple-A Gwinnett. Walden has one save and a 2.92 ERA in 14 games. Thomas was sent to Gwinnett on Sunday with instructions to work on his slider. ... The Cubs have lost six of seven. ... The Braves are 12-0 when scoring the first run in a game. ... Braves manager Fredi Gonzalez said LHP Jonny Venters, recovering from his second Tommy John surgery, will report to the team’s minor league complex in Orlando and will begin throwing batting practice on Friday. ... The series ends on Sunday with Atlanta’s Aaron Harang facing Chicago’s Edwin Jackson in a matchup of right-handers.