Ozzie Albies has done plenty to establish himself as a force in his first full season in the majors, but he had not hit a walk-off homer.

He changed that Monday.

Albies led off the 11th inning with a first-pitch homer that sailed over the brick wall in right-center field at SunTrust Park, giving the Braves a 5-4 win in a series opener against the streaking Reds.

He jumped on a slider from right-hander Dylan Floro and produced the Braves' fifth walk-off homer of the season and the first of Albies' career.

He leads the Braves with 17 home runs and also had two doubles Monday.

» More: Albies called his game-winning homer

The Braves won for just the second time in nine extra-inning games and snapped Cincinnati’s seven-game winning streak. The Reds were coming off a four-game sweep of the Cubs.

It was the the seventh walk-off win for the Braves and 10th win in their final at-bat.

Mike Foltynewicz allowed only one run in five innings in his return from the disabled list and left with a 3-1 lead, but saw it evaporate when reliever Lucas Sims failed to retire any of the first four batters he faced in a two-run sixth.

The game was delayed by rain for 80 minutes before the first pitch and didn’t end until 12:40 a.m.

After the Reds scored three runs in the sixth and seventh innings to take a 4-3 lead, the Braves tied it with an unearned run in the seventh following a two-base fielding error by former Gold Glove first baseman Joey Votto. Freddie Freeman’s sharp grounder skipped over Votto’s glove into right field and Freeman hustled to second on the play, then scored on Danny Santana’s two-out double.

Pitching on 12 days of rest after coming off the DL earlier Monday, Foltynewicz issued four walks but allowed just one hit and one run, that on Scott Schebler’s 426-foot fifth-inning homer that cut the Braves’ lead to 3-1.

Foltynewicz threw 54 strikes in 91 pitches and whittled his ERA from 2.16 to 2.14.

The lead went up in flames after Sims gave up three straight singles and a bases-loaded walk to start a two-run sixth inning.

The Reds moved ahead an inning later when Schebler doubled, advanced on a sacrifice bunt and scored on Votto’s ground-out for a 4-3 lead.

The Braves provided Foltynewicz an early lead in his first action in nearly two weeks, scoring two runs in the first inning. Ender Inciarte drew a leadoff walk and scored on a double by Albies, who scored two batters later on Kurt Suzuki’s sacrifice fly.

Foltynewicz came off the DL without making a rehab start and pitched for the first time since June 12, when he left a game against the Mets after five scoreless innings due to tightness in the triceps muscle in the back of his pitching arm.

He threw hard Monday, his fastball topping out at 99 mph in the first inning. But the strike zone was tight and he was off his mark a bit in the early going, issuing four walks in the first three innings and throwing 65 pitches in that span despite allowing no hits.

He walked two in the third inning before striking out National League batting leader Scooter Gennett to end the inning and preserve a 2-0 lead. Then after working a perfect fourth in 12 pitches including two strikeouts, Foltynewicz gave up a two-out, first-pitch homer to Schebler in the fifth to trim the lead to 2-1.

The Braves got that run back in the bottom of the inning when Ender Inciarte led off with a single, advanced on another Albies double and scored on Nick Markakis’ double-play grounder with the bases loaded to return the lead to two runs, 3-1.

Sims, recalled from Triple-A on Saturday for his fourth stint with the Braves this season, gave up three hits to start the sixth inning, followed by a Jesse Winker walk that brought in a run. One out later, Adam Duvall grounded out to bring in the tying run.

Markakis had a two-out single in the third inning for his 100th hit in the Braves’ 77th game, the first NL player to reach triple-digit hits and the fastest Markakis has collected 100 hits in his 13-year career.

He added a two-out single in the ninth inning.