PHOENIX -- It was the top of the sixth inning, and the D-backs were in a jam.

Starter Mike Leake had just given up a hit to put runners on first and second with one out, and the top of the Phillies' order was coming up. D-backs manager Torey Lovullo looked at his matchup card and decided it was time to go to the bullpen.

That decision, and the ensuing performance by Andrew Chafin, ended up turning the tide as the D-backs rallied for an 8-4 win over the Phillies on Tuesday night at Chase Field.

• Box score

With the victory, the D-backs got back to .500 at 57-57 and evened the series, which concludes Wednesday night. They also pulled within 2 1/2 games of the Phillies for the second National League Wild Card spot.

But before Chafin entered the game, things were not looking good for Arizona.

Leake, making his D-backs debut after being acquired from the Mariners minutes before last week’s Trade Deadline, allowed a homer to Corey Dickerson to open the game. It was one of 11 hits Leake allowed, as he was in trouble throughout his 5 1/3 innings.

For the most part, though, Leake wiggled out of jams, giving up only a run in the fourth and another in the fifth as the Phillies led, 3-2.

But it looked like Philadelphia was poised to blow it open in the sixth, when the left-handed Chafin came in from the bullpen with one out and runners on first and second.

Chafin first faced the left-handed-hitting Dickerson, starting him off with two sliders that Dickerson fouled off.

Then, on 0-2, Chafin went with a sinker and got Dickerson to roll a ball toward first base. A throwing error by Christian Walker, though, prevented the D-backs from getting any outs, and the bases were loaded.

That brought the right-handed-hitting Rhys Hoskins to the plate, and Lovullo stuck with Chafin because he wanted the southpaw to face the left-handed-hitting Bryce Harper, who was waiting on deck.

Chafin struck out Hoskins, and as Harper walked to the plate, D-backs catcher Alex Avila’s brain was working overtime.

Avilia, himself a veteran left-handed hitter, was trying to put himself in Harper’s shoes.

“The Dickerson at-bat, we were starting him off offspeed pretty early, and then we were able to jam him with the fastball,” Avila said.

Avila figured Harper was paying closer attention to that pitch sequence than the one used against Hoskins, because both Harper and Dickerson are lefties. When Avila is facing a pitcher, he’ll look to see how that pitcher worked the last lefty he faced, rather than simply the previous hitter.

“I figured, well, he might be looking breaking ball there,” Avila said, because that’s how they started out against Dickerson.

So instead, Avila called two straight four-seam fastballs, the first of which went for a ball and the second which froze Harper for a called strike.

Figuring Harper was almost assuredly looking slider now, Avila called for a sinker, and Harper once again was caught looking for strike two.

Finally, Avila called for a slider, and Chafin threw a good one just below the strike zone that Harper swung and missed on, ending the inning and the threat.

“Even if he was looking breaking ball there, it would have been tough to even foul off that one,” Avila said.

It turned out to be what Lovullo referred to as a “push moment,” propelling the momentum of the game into the D-backs' dugout. The D-backs went on to torment the Phillies’ bullpen, scoring two runs in the sixth, three in the seventh and one in the eighth, with David Peralta and Avila hitting home runs.

“Obviously, facing those two guys, Hoskins and Harper, back to back with traffic is no easy task,” Avila said. “[Chafin] made some really big pitches.”