ATLANTA -- A historic and improbable double play sparked by Michael Harris II capped the Braves' dramatic series-tying comeback in Game 2 of the National League Division Series on Monday night against the Phillies.

Having rallied from a four-run deficit, the Braves were clinging to a 5-4 lead in the ninth inning with Bryce Harper on first base and Nick Castellanos up to bat with one out. Castellanos hit a fly ball to deep right-center field that would have been a home run in five major league ballparks and that StatCast gave a .610 expected batting average.

Harris, though, read it quickly, telling reporters after the game: "I knew off the bat it was going to be close to the fence, so I knew once I went back, I wasn't stopping. I was going to do anything I could to get a glove on it."

Harris leaped to catch it, hitting the outfield wall, then immediately set his feet to relay the ball back to the infield toward second base. As Harris caught the ball, Harper was about five steps past second base.

"Usually you don't pass the base," Phillies manager Rob Thomson said. "You stay in front of it, make sure it's not caught. But he thought the ball was clearly over his head, didn't think he was going to catch it. And Harris made a heck of a play. Unbelievable. He tried to get back, and he slipped, but usually you stay in front of the second base."

Second baseman Ozzie Albies whiffed trying to scoop Harris' throw, but third baseman Austin Riley was standing between second base and the mound backing up Albies. That wasn't by design.

"I think the only reason I was in the position that I was because I was screaming one and just momentum just kept pulling me that way," Riley said. "And it ended up just being right spot at the right time."

Riley scooped the ball backhanded and threw it to first in one motion, like fielding a slow roller at third base. That ended the game, completing the first 8-5-3 double play in MLB postseason history and the first double play ever involving an outfielder to end a postseason game.

Harris said after the game he didn't know where Harper was, which is why he threw the ball toward second base.

"We just saw a slomo here [in the clubhouse]," he said. "I didn't know that he went past second, so I threw it in ... I guess Riley was right there in the right spot to make the throw, made an incredible throw."

Harper commended Harris for his play.

"Just taking a chance," he said of his own baserunning. "Michael made a great play and doubled me up. Tough way to end it."

The Phillies were up 4-0 in the sixth inning and 4-1 in the seventh when Braves catcher Travis d'Arnaud hit a two-run homer off of former Mets batterymate Zack Wheeler to make it 4-3. That ended an otherwise excellent night for Wheeler, who struck out 10, walked one and allowed just three hits.

"We were trying to stay as positive as possible in that dugout," Riley said of the Braves' mentality leading up to the home run. "Everybody was saying we just got to keep going, got to keep going. [Wheeler] had an unbelievable night. He was very dominant ... Once we got that crowd back in it, good things happen."

Riley struck the final blow with a go-ahead homer off Jeff Hoffman.

"I was just trying to put a barrel on the ball," he said. "That's all it was. It's definitely up there with my top [homers]."

The series now heads to Philadelphia for Games 3 and 4. The Phillies will start Aaron Nola on Wednesday. Manager Brian Snitker said he'll likely reveal the Braves' Game 3 starter Tuesday.