ATLANTA -- Rookie Sean Newcomb took another stride forward in establishing himself as a major league starting pitcher on Sunday.

The left-hander pitched five scoreless innings and stopped a personal five-game losing streak when the Atlanta Braves beat the Cincinnati Reds 8-1 at SunTrust Park to salvage the final game of the three-game set.

Newcomb (2-7) allowed five hits but permitted no runs in his five-inning stint. He walked five, struck out two and worked out of trouble in his final three innings, when the Reds stranded eight runners. He earned his first win since June 27.

"It's not perfect, but he doesn't ever give in and his stuff is live," Atlanta manager Brian Snitker said. "There's a lot to like there."

He finally got some run support, too. The offense entered the game averaging only 1.3 runs behind Newcomb, but that changed on Sunday when catcher Tyler Flowers broke the game open with a grand slam in the fifth inning.

"That always helps," Newcomb said.

Flowers connected for his second career slam in the fifth, part of a six-run frame against reliever Drew Storen. The right-hander gave up six runs, six hits and two walks in two-thirds of an inning. It was the ninth grand slam allowed by Cincinnati this season, a club record.

Brandon Phillips went 3-for-5 with an RBI and two runs scored and Freddie Freeman was 3-for-5 with a double and two runs scored. Ozzie Albies and Dansby Swanson each had two hits in Atlanta's 12-hit attack.

Phillips remained red hot at the plate and is batting .393 (11-for-28) over the last six games. He also made a stellar fielding play at third base to start a double play in the fifth inning.

Newcomb escaped a bases-loaded mess in the third inning thanks to some good defense. Albies jumped as high as possible at second to snag Joey Votto's line drive that might have cleared the bases.

"I turned and he was off his feet," Newcomb said. "He was really up there."

Newcomb then helped himself get the final out, sprawling on the infield grass to stop a slow grounder and rolling the ball to first in time to nip Adam Duvall.

"I couldn't get it with the glove so I had to make a little dive at it," Newcomb said. "I just had to get it toward the bag."

Newcomb left the bases loaded again in the fifth when he retired Scooter Gennett on a harmless fly ball to center field to end the inning.

"Tip your hat to the lefty," Cincinnati manager Bryan Price said. "Newcomb pitched a nice ballgame. His fastball was sitting at 93-94, but it had some jump to it. He really established the fastball the first time through the lineup, then he started mixing the accessory pitches as the game went on. He pitched well. That was our A-grade lineup."

Cincinnati starter Luis Castillo (2-6) was victimized by a high pitch count and lasted only four innings on the hot afternoon. He threw 90 pitches, giving up two runs and striking out eight. He fanned six of the first nine batters he faced.

"This team in Atlanta did about as good a job as any team he's faced as far as fighting off the good pitches, battling and keeping the at-bat alive," Price said. "Even if the at-bat ended, it was a five-, six- or seven-pitch at-bat."

Atlanta broke through for two runs in the third against Castillo, with Nick Markakis bouncing a two-out double that caromed against the brick portion of the right-field wall and scored Phillips and Freeman.

"Sometimes you make mistakes," Castillo said. "They were able to foul off a lot of good pitches. I went out there and didn't have my best stuff and just competed."

Atlanta's Matt Wisler threw three scoreless innings of relief. But Cincinnati broke up the shutout in the ninth when Phillip Ervin singled home Jose Peraza against rookie Max Fried.

Cincinnati got 3 1/3 scoreless innings of relief from Tim Adleman.

NOTES: The two teams split their six games this season. ... The Reds completed their second consecutive 10-game road trip at 5-5. ... Cincinnati 1B Joey Votto was hit by a pitch and has reached base in 25 consecutive games. ... Atlanta 1B Freddie Freeman extended his hitting streak to eight games with a single. ... Atlanta RF Nick Markakis had his 30th double, the eighth year he has met that mark. ... Cincinnati returns home to begin a three-game series on Tuesday against the Chicago Cubs. The Reds send RHP Homer Bailey (4-6, 8.44 ERA) against Chicago's John Lackey (10-9, 4.67). Atlanta starts a three-game series with Seattle on Monday. Atlanta RHP Mike Foltynewicz (10-8, 4.75) will be opposed by Seattle's Andrew Albers (1-0, 1.80), who was acquired from the Braves' Triple-A team a week ago.