PHILADELPHIA -- Manager Bud Black cited two key reasons for Antonio Senzatela's recent turnaround prior to the right-hander's start Thursday night at Citizens Bank Park: his slider and his ability to locate.

Unfortunately for Senzatela, a well-placed slider ultimately accounted for the only real knock against him -- but Ryan McMahon’s go-ahead pinch-hit homer in the ninth took Senzatela off the hook in the Rockies' 4-3 win over the Phillies.

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Senzatela retired the first two batters he faced on six pitches before getting locked into a seven-pitch duel with National League MVP candidate Bryce Harper. After getting ahead in the count, 1-2, Senzatela uncorked a pair of sliders well out of the zone to run the count full. He then challenged Harper with a fastball up in the zone that was fouled off.

Senzatela went back to the slider on pitch No. 7, placing it right on the low, outside corner. Harper launched a fly ball to the opposite field that narrowly cleared the wall in left-center field. It would have been a home run in just three of the 30 ballparks across the league, according to Statcast -- but Citizens Bank Park just so happened to be one of them.

“He was great,” Black said of Senzatela. “It really wasn't a bad pitch to Harper. … It just shows the talent of Harper to be able to take a pitch down and away from him, corner of the strike zone, and hit an opposite-field homer. That's special talent. So I thought Senzatela was great.”

The Rockies’ righty responded by retiring the next nine batters he faced -- and he didn't allow another hit until the sixth inning. The only other run allowed by Senzatela came in the sixth when second baseman Brendan Rodgers bobbled a potential inning-ending double-play ball and instead settled for a run-scoring fielder's choice out.

Senzatela allowed just two runs over six innings -- his sixth straight start in which he completed at least six innings. The righty has a 2.54 ERA in that span.

"I was feeling good,” Senzatela said. “Everything was working well -- my fastball and my breaking pitches were all there. So I felt really good."

Colorado’s offense was quiet for much of the night, but woke up once it was down to its final out. With the club trailing 2-1, Colton Welker -- who had an RBI single in the fourth for his first career hit -- kept the game alive with a two-out hit off Phillies closer Ian Kennedy. McMahon then followed with a no-doubt two-run homer on an 0-2 pitch, and Sam Hilliard tacked on with a towering shot of his own one batter later.

Though the Rockies have certainly had their struggles on the road this season, they are no strangers to late-game dramatics -- as evidenced by their MLB-leading 12 walk-off wins.

“Our guys have done a really good job of playing the entire game, whether it's 54 outs or extra innings,” Black said. “It's the sort of thing that shows up in our walk-off wins at home, but we keep battling, we keep playing. A lot of these guys are learning.”

Colorado’s latest comeback win came against a Phillies team that is in the thick of both the NL East and NL Wild Card races. While the Rockies hope to be on that side of the postseason race in the future, they recognize that there is still value in winning games against playoff-hopeful clubs.

“We're trying to play spoiler, right?” McMahon said. “We're playing some teams who are fighting for playoff spots, so that's kind of going to be our gig. So it was a lot of fun, kind of spoiling tonight.”

To not only earn the win, but to do so in such dramatic fashion is something that Black hopes will stick with some of his younger players.

“Games like this sink in. Guys remember these types of games in a major market, in a great sports town like Philadelphia -- to come here with a team that's biting at the heels of the Braves, and our guys played them toe to toe,” Black said. “It was awesome. It's great for these guys.”

It was also great for Senzatela to avoid being saddled with what would have been an incredibly tough-luck loss.

“It was really fun,” Senzatela said of watching the ninth-inning rally. “It was really fun, I enjoyed it. That was nice.”