AP photo by John Bazemore / The Atlanta Braves' Michael Harris II slides into second base with a double during the seventh inning of Wednesday night's home game against the Oakland Athletics.

ATLANTA — Atlanta Braves pitcher Ian Anderson said the team's sudden turnaround is "hard to describe."

One obvious factor in their seven-game winning streak — after having not won three games in a row all season until last week — is rookie outfielder Michael Harris II.

Harris hit a two-run triple in the fifth inning to spoil Jared Koenig's MLB debut Wednesday night, and the surging Braves beat the skidding Oakland Athletics 13-2.

A sellout crowd of 42,075 gave Harris an ovation, and his clutch swing triggered an outburst of extra-base hits that included four home runs.

"It's a really good feeling," Harris said. "It got our bats rolling."

Anderson pitched six solid innings, and the Braves rallied from a 2-0 deficit for the second straight night to sweep the two-game series. The A's have lost eight straight games and 11 of their past 13.

Atlanta, the reigning World Series champion, struggled through most of the first two months this season. It's no coincidence the Braves found the path to consistent winning almost immediately after Harris, the team's top prospect, was recalled from Double-A Mississippi on May 28.

Harris has impressed with his big defensive plays in center field, and he showed his potential at the plate with a triple and a double Wednesday night.

"He has been really impressive, as we've talked, defensively, and his at-bats have been really, really good," Braves manager Brian Snitker said.

"I feel like I belong," said Harris, who's hitting .268.

The 28-year-old Koenig led 2-1 through four innings after completing his long path to the majors that included spending the 2017-19 seasons in independent leagues. The 6-foot-5 left-hander didn't get an out in the fifth.

After walking Marcell Ozuna, who moved to third base on Adam Duvall's double off the left-field wall, Koenig faced Harris in a matchup of rookies. The left-handed-hitting Harris pulled a liner past first baseman Seth Brown into the right-field corner, driving in Ozuna and Duvall to give the Braves a 3-2 lead.

Harris was safe on a headfirst slide into third base. With two outs, Austin Riley's two-run homer off Domingo Acevedo extended the lead to 5-2. Ozzie Albies, William Contreras and Duvall also homered in Atlanta's 13-hit outburst Wednesday.

Albies' three-run shot, which barely cleared the left-field wall over the glove of a leaping Chad Pinder, and Duvall's two-run drive were the big hits in a seven-run seventh. Harris added a double in the inning, complete with another headfirst slide into second base, and later scored on Riley's single for a 7-2 lead.

Anderson (5-3) allowed two runs and six hits.

Koenig (0-1) permitted four runs on five hits and two walks in four-plus innings.

Ramón Laureano doubled and scored on a wild pitch, and Sean Murphy had a run-scoring single in Oakland's two-run fourth.

The winning streak has pushed the Braves three games over .500 at 30-27.

"We're kind of doing the right things now, and it's kind of leading to wins," Anderson said. "You've got to hold on to it as long as you can."

Koenig became the 20th rookie to play for Oakland this season, one shy of the team record set in 2008. He is the 13th rookie pitcher for the A's, which sets a team record.

The A's optioned right-hander Domingo Tapia to Triple-A Las Vegas when Koenig was recalled from Las Vegas. Right-hander Gabe Klobosits was designated for assignment.

Oakland catcher Christian Bethancourt, who popped out in the eighth as a pinch-hitter, remained in the game to pitch mop-up duty in the bottom of the inning. The right-hander got three consecutive outs. The former Brave previously pitched a combined six games with the San Diego Padres in the 2016-17 seasons.

Braves catcher Travis d'Arnaud (left forearm) was held out another day after being hit by a pitch Sunday. He could return to the lineup Thursday night, when Atlanta opens a four-game home series against the Pittsburgh Pirates.

Atlanta outfielder Eddie Rosario, placed on the 10-day injured list April 25 with blurred vision and a swollen right retina, is increasing his hitting and fielding practice.

Snitker said right-handed pitcher Collin McHugh, placed on the COVID-19 injured list Tuesday, was "still not feeling great."