PHILADELPHIA — When Merrill Kelly descended into the Diamondbacks’ dugout following the fifth inning on Monday night, he was met by an unexpected handshake from manager Torey Lovullo.

Kelly followed his good-natured human instincts, reaching out his hand to meet Lovullo’s. He soon realized, however, that this was not a nice-work, you-just-struck-out-Bryce-Harper handshake. It was a well-done, time-to-hand-it-off-to-the-bullpen handshake.

Kelly was shocked.

“I just went through their top three [hitters], punched out two of them,” Kelly said after the game. “Ninety pitches through five, I’m thinking I’m for sure going back out for six.”

And, yet, five innings of Merrill Kelly were all that the world got to see on Monday.

The show was excellent while it lasted, though. In those five innings, Kelly allowed only one run on three hits with eight strikeouts. The Diamondbacks are not heading to a do-or-die Game 7 on Tuesday solely because of him, but his outing was crucial in paving the way to their 5-1 win in Game 6.

While Kelly struggled in his last appearance in the series — he allowed four runs, including three homers, in 5 2/3 innings in Game 2 — he did not feel the need to make any major game plan changes heading into Game 6.

“I went back and looked at [that game],” Kelly said. “It was more about executing, I think, especially the early homers that you talk about purely just weren’t executed pitches.”

In Game 6, Kelly simply hoped to avoid the kind of mistakes that cost him in Game 2. He also made one important change: Do not let Kyle Schwarber or Bryce Harper beat you.

In Game 2, Schwarber homered twice against Kelly, and he has had an incredible series. In Games 1-5, he went 7-for-17 with five homers. Containing him was going to be a key in Monday night’s game no matter what.

Harper went 0-for-2 with a walk in Game 2 against Kelly, but he had done considerable damage against the Diamondbacks in the series, going 5-for-16 with two homers and five walks in the first five games.

Kelly made his intentions with Schwarber and Harper clear from the jump, walking Schwarber on four pitches to start the game — and Harper, on five pitches, two batters later.

“Harper and Schwarber are both super locked in right now,” Kelly said of his game plan. “They’re not missing too many mistakes, so I’m not too mad about putting them on base right now.

“If the worst thing they get to me all day is a walk, I went in tonight being okay with that and just trusting that, in between those guys, I had the confidence to get the other guys out.”

Kelly did just that.

Outside of the three total walks he issued to Schwarber and Harper, Phillies hitters went just 3-for-15 with two singles and a double against the D-backs’ righty.

As Kelly often does, he kept opponents off balance with a diverse array of pitches. Of his 90 offerings in the game, eight were curveballs, 11 were cutters, 11 were sliders, 14 were changeups, 21 were sinkers and 25 were four-seam fastballs. He induced a whiff and recorded at least one out on all six of his pitches.

Kelly’s best pitch is generally his changeup, but it is hard to say which one it was on Monday. All came up big in certain moments. Perhaps his best pitch was his curveball. He threw it only 11 percent of the time in the regular season, but his eight curveballs on Monday turned into one ground out, three called strikes and four whiffs. Hard to do better than that.

After walking Schwarber in the first, he got Trea Turner to fly out on a down-and-away slider. He then threw strike one to Harper followed by four pitches way out of the zone to Harper. Another walk, giving the Phillies runners at first and second with one out. Not to worry, though; this was, in a sense, part of the plan.

After getting Philadelphia’s next hitter, Alec Bohm, to whiff at a 1-1 slider out of the zone, Kelly completed the strikeout by dotting the lower-inside corner with a four-seam fastball. He then got Bryson Stott to pop up on a front-door sinker. Inning over.

In the top of the second, the Diamondbacks notched their first lead of the series at Citizens Bank Park. After working a 2-2 count, Tommy Pham — who sat out Game 5 in favor of Pavin Smith — launched a solo home run to left field on a hanging curveball by Aaron Nola.

It was the first run the Diamondbacks had scored against Nola in the series — he tossed six scoreless innings against them in Game 2 — and the first homer Nola had allowed all postseason long. Nola entered Monday’s game with an impressive 0.96 postseason ERA.

The next hitter, Lourdes Gurriel Jr., followed suit with another solo homer on a down-and-in sinker. Two batters later, Evan Longoria brought home another with an RBI double on a first-pitch, middle-middle fastball into the left-center field gap. Very quickly, the Diamondbacks staked a 3-0 lead.

Looking back, Diamondacks closer Paul Sewald said that it was not that three-run top of the second that most helped the Diamondbacks built momentum, but Kelly’s scoreless bottom of the first.

“We have given up runs in the first inning three times [in the series], and we’re 0-3,” Sewald said. “We’ve put up [three] zeros, and we’re 3-0. With how their lineup starts, if you can find a way to put up a zero, that’s huge.”

With that three-run second inning, the Diamondbacks brought the momentum in their favor even more.

“They got on top of us the first few two games here and this place got awfully loud,” Sewald added. “We needed to quiet these guys down. It’s the first time they’ve sat, I think, for a playoff game.”

Phillies fans did get back into the game to some degree in the bottom of the second when J.T. Realmuto led off the frame with a double. Two batters later, Brandon Marsh drove him in with an RBI single, advancing to second on a throw by Corbin Carroll.

That brought up Johan Rojas, the Phillies’ No. 9 hitter. It took seven pitches, but Kelly eventually got Rojas to roll over the top of a curveball for a ground out. With two outs, that brought up Schwarber. And, once again, Kelly stuck to the plan.

After a first-pitch changeup down and away, Kelly threw Schwarber a well-placed 1-0 strike on a cutter on the inside part of the plate. He was again determined, however, not to let the Phillies slugger beat him. Schwarber fouled off a pair of well-placed cutters in the at-bat, but he eventually took enough pitches out of the zone to draw his second walk of the game.

That brought up Trea Turner, whom Kelly struck out on three pitches. Inning over.

Sporting a 3-1 lead, Kelly was more aggressive with Harper the second time around in the bottom of the third inning. After a first-pitch cutter away, Kelly dotted the lower-outside corner with a strike, induced a foul ball on an elevated cutter, then painted the bottom of the zone with a slider that locked up Harper.

When Schwarber and Harper’s spots came back around in the fifth inning, the Diamondbacks had added another run on a Ketel Marte RBI triple. Leading 4-1, Kelly opted to go after both of them.

After missing with a cutter off the outside corner in a 2-2 count to Schwarber, Kelly threw a pitch Schwarber that had not seen all night: the curveball. The location was terrible — it was right down the middle — but he got him to whiff.

Two batters later, Kelly went to that curveball again in a 2-2 count to a Harper. As with Schwarber, it was a pitch he hadn’t seen all night. This time, Kelly located it beautifully.

At that point, much to Kelly chagrin, his night was done.

“He had done his job,” Lovullo said after the game. “It was 65 pitches through three. That was a concern. It was 48 after two. That was a concern. I was managing his workload. I was watching his stuff. In my opinion, it was just time to come out of the game.”

In total, Schwarber and Harper had six plate appearances against Kelly, and they never put the ball in play: three walks, three strikeouts. Neither scored or drove in a run.

When Kelly departed, the Diamondbacks’ bullpen continued what he started. Ryan Thompson tossed a scoreless sixth inning and got the first out of the seventh. Andrew Saalfrank got the final two outs of the seventh.

Kevin Ginkel and Paul Sewald pitched scoreless eighth and ninth innings, respectively. Neither has allowed a run all postseason.

With the Diamondbacks’ Game 6 win, they became the first team to beat the Phillies at Citizens Bank Park in the playoffs this year. The Phillies entered Monday night’s game with a 6-0 record in the postseason at home this October, having outscored their opponents 39-9.

The Diamondbacks will play one more game against the Phillies on Tuesday night with a ticket to face the Texas Rangers in the World Series on the line.

“It’s hard to put into words,” Corbin Carroll said. “Everyone’s just excited. It’s going to be hard to sleep tonight.”

“We’re walking around, looking at each other, smiling, and everybody feels it,” Christian Walker added. “It’s right there for us to go get.”

Given how the first two games of this series went — a pair of Phillies victories in which they outscored the Diamondbacks 15-3 — many national analysts were quick to rule out the D-backs’ chances.

“Sometimes, when you count a team out from the get-go and, when that team easily falls behind 0-2, you get that perception,” Pham said. “But we always felt like if we got some good pitching, played great defense, and we played our game, that we could win this.”

Said reliever Kevin Ginkel: “We’ve shown this city and that team that we don’t go away easily.”

Indeed, the Diamondbacks are still here. On Monday, Merrill Kelly carried them. On Tuesday, they will play the second postseason Game 7 in franchise history. The last one went down as arguably the most memorable moment in Arizona sports history. Let’s see what happens this time.

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Top photo: Rob Schumacher/The Republic