ATLANTA -- The Chicago Cubs continued their second-half surge, and catcher Willson Contreras was once again right in the middle of it.

The Cubs struck a pair of home runs, the big blow being a three-run shot from Contreras, and won for the fifth straight time, a 5-1 decision over the Atlanta Braves on Tuesday at SunTrust Park.

By winning five straight for the first time this season, Chicago pulled with 2 1/2 games of the first-place Milwaukee Brewers in the National League Central.

Second baseman Javier Baez went 3-for-4 with a homer, but it was the two-out, third-inning bomb from Contreras that proved the difference. Contreras was 1-for-4 with a walk and is now 9-for-22 (.402) with two homers and seven RBIs in the five games of the current road trip.

"He's definitely turning out to be a force," Chicago manager Joe Maddon said.

And while it may be difficult to sit one of the team's hottest hitters, Maddon said Contreras will not start in the series finale on Wednesday afternoon.

"If you want to see that at the end of the year, take care of him now," Maddon said.

Chicago starter John Lackey (6-9) was the beneficiary of the support. The veteran right-hander, making his first start since going on the disabled list with plantar fasciitis on July 6, pitched five innings and allowed only one run on five hits.

"He was able to locate his fastball and he was able to locate the slider pretty well," Contreras said. "We were aggressive. Things worked out."

Lackey failed to retire the side in order in any inning during his stint. However, only once did he allow multiple runners to reach base, and twice the first hit of an inning came with two outs.

"I felt pretty good," Lackey said. "When I originally warmed up, my arm felt great. I was anxious to see how that would translate."

Atlanta manager Brian Snitker said, "He kind of kept everybody off balance. He was moving it around and changing speeds. We just couldn't get ahold of him."

The Cubs got shutout relief work from Brian Duensing and Pedro Strop before Atlanta threatened in the eighth inning against Carl Edwards Jr. The right-hander allowed a pair of runners to reach before retiring Matt Adams and Nick Markakis on called third strikes. Edwards struck out three and now has 56 K's in 38 1/3 innings.

"We couldn't bunch anything together," Snitker said. "We had some guys on, we just couldn't get the big hit."

Right-hander Hector Rondon pitched a scoreless ninth inning in a non-save situation, striking out three.

The losing pitcher was Atlanta rookie Sean Newcomb (1-5), who allowed five runs in 5 1/3 innings.

"He gutted it up, made some big pitches at times, could have got way out of hand but battled his way through and didn't let it happen," Snitker said. "He wasn't as sharp as he's been, and the secondary stuff was kind of not there. It's going to happen."

Newcomb was chased in the sixth. He allowed three consecutive hits to open the inning, then struck out pinch hitter Jon Jay, but he was lifted for right-hander Luke Jackson. The reliever limited to Cubs' threat to only one run, that coming when Albert Almora Jr. scored on Ben Zobrist's grounder to first.

"Tonight I didn't throw a lot of strikes in spots I need to," Newcomb said. "Trying to do a little too much with my off-speed. Kind of trying to not live pitch by pitch, thinking too far ahead. I just have to attack one pitch at a time, not worry about what's about to happen."

The Atlanta bullpen was effective. Jackson pitched 1 2/3 scoreless innings, and Sam Freeman followed with two scoreless innings.

Atlanta took a 1-0 lead in the second inning when Markakis hit a long solo home run, his fifth.

Chicago homered twice in the third inning and went ahead 4-1. Baez led off with a solo shot, his 11th, and Contreras added his three-run blast. The two runners ahead of Contreras -- Zobrist and Kris Bryant -- reached on walks from Newcomb.

NOTES: The game started 2 hours and 30 minutes late because of a rainy front that moved through the area. It was the 13th time the Braves had a rain delay this season. ... Chicago activated RHP John Lackey from the 10-day disabled list and optioned RHP Eddie Butler to Triple-A Iowa. Lackey had been sidelined due to right foot plantar fasciitis. ... Atlanta said it would activate RHP Arodys Vizcaino on Wednesday. He has been out since July 5 with a right index finger strain. The team will decide Wednesday whether to send a reliever to Triple-A Gwinnett to continue working with a seven-man bullpen or return to an eight-man bullpen. ... The attendance was 41,541, the Braves' ninth sellout at SunTrust Park.