Veteran pitcher Aaron Harang’s return to Cincinnati was undermined by a mistake of his own doing, and the Braves’ recent five-game winning streak and offensive resurgence are starting to feel like fading memories.

Failing to cover first base on an infield single, Harang contributed to his and the Braves’ demise in a three-run fourth inning that propelled the Reds to a 5-3 victory Sunday and a split of the four-game series at Great America Ballpark.

The Braves staged a ninth-inning rally that yielded two runs before Justin Upton grounded into a bases-loaded force at second to end the game.

“I take blame for the whole thing,” said Harang, who failed to cover first base on a one-out infield hit in a then-scoreless game, which was followed by a fly ball that became a sacrifice fly. “If I make that, cover first like I routinely do, he flies out to right, inning’s over, no run scores. It’s a tough one to swallow. Especially when we’ve been playing so well.

“To go out and end up losing on one mental error in the game, and have it cost you the victory, it really stinks.”

After winning five in a row and seven out of eight, the Braves dropped consecutive weekend games against a Reds team that had a seven-game losing streak before shutting out the Braves 1-0 on three hits Saturday.

Atlanta hitters didn’t do much better for most of the game Sunday, when six of their nine hits came in the final three innings after the Reds built a 4-0 lead. They trailed 5-1 before Evan Gattis led off the ninth with his 20th home run.

“It’s still rough (to lose), but it’s always good to fight back,” said Gattis, the second catcher in franchise history to hit at least 20 homers in each of his first two seasons, joining Earl Williams (1971-1972).

Emilio Bonifacio hit a two-out single, advanced to second on indifference, and scored on Heyward’s hit to cut the lead to two runs. With closer Aroldis Chapman unavailable after throwingt four innings in the previous three games, hulking Reds reliever Jonathan Broxton walked Phil Gosselin and Freddie Freeman consecutively to load the bases before Upton’s grounder ended the game.

“You had the right guys at the plate,” said manager Fredi Gonzalez, whose raves are 4-3 on a 10-game trip. “Absolutely had the right guys at the plate. I think Gosselin gave us one hell of an at-bat right there to get those guys to the plate, and you feel good (about chances), the way Justin is swinging the bat and Freeman is swinging the bat, that something good was going to happen there. I didn’t feel like we lost the game, I felt like we just ran out of outs.”

They have an off day in New York Monday before opening a three-game series against the Mets. The Braves have time to stew over dropping three of their past five games and scoring a total of five runs in the three losses.

They trailed 4-0 before scoring a run in the seventh inning on consecutive one-out doubles by Gattis and Tommy La Stella. B.J. Upton lined out to center field and Ryan Doumit hit a routine groundout to strand a runner at third as the Braves had another bad day with runners in scoring position (2-for-10).

After Todd Frazier’s seventh-inning homer off reliever David Hale pushed the lead back to 5-1, the Braves had a good scoring opportunity in the eighth when they started the inning with a Heyward walk and Gosselin single. But Freeman grounded into a force at second and both Justin Upton and Chris Johnson struck out with runners on the corners.

“We had opportunities today,” said Freeman, who also grounded into a double play after Gosselin’s one-out single in the third. “We fought all game. We put together nine or 10 hits. Just one of those days, the last inning we couldn’t get the big hit.”

Harang (10-8) allowed eight hits and four runs in 5 1/3 innings, with two walks and five strikeouts. It was just the fourth time this season he allowed more than three earned runs in five or fewer innings, but two of those have been in his past three starts.

The Braves fell to 5-8 in games before off days, which includes five losses by three or more runs as well as a 10-inning defeat. Before Sunday, they were seven games behind National League East leader Washington, and one game behind San Francisco for the second NL wild-card spot.

The Braves had high hopes for a strong finish to the series with Harang on the mound in the ballpark where he pitched for 7 ½ seasons with the Reds and made five consecutive opening-day starts through 2010. The stocky right-hander had been 5-1 with a 3.10 ERA in his past 11 starts before Sunday, with three earned runs or fewer in nine of those games.

But after allowing just one walk and an infield single through three innings, Harang gave up consecutive singles to start the fourth. One out later, he didn’t cover first base on Jay Bruce’s infield single that Freeman fielded behind the base on the line.

“I think he thought that the ball was foul,” Gonzalez said. “He broke (toward the base) right away and kind of stopped, and it was a fair ball. That one inning was big. Give up three runs there.”

Harang shouldered the blame and made no excuses.

“Something as small as covering first, that I’ve done thousands of times in my career, and one time you don’t do it and things come unraveled,” he said. “I thought when Jay hit that ball, the way Fredi was going after it, I just assumed it was foul, so I kind of broke down, and by the time I get started again I’m not going to beat him to first.”

With the bases now loaded, the Reds got a sacrifice fly from Ryan Ludwick and RBI singles from Brayan Pena and Zack Cozart to build a 3-0 lead.

“That mental mistake, it’s frustrating,” Harang said. “It ended up costing us this game. We should have got a victory out of that. My mental lapse just cost us.”

The Reds tacked on another run in the sixth when they chased Harang from the game with a pair of singles and a walk that loaded the bases again. Zack Cozart’s run-scoring groundout made it a 4-0 lead.