Celtics big man Xavier Tillman played a key role in Boston's victory over the Dallas Mavericks in Game 3 of the NBA Finals on Wednesday night.

With Kristaps Porzingis sidelined with a left posterior tibialis dislocation, Celtics head coach Joe Mazzulla leaned on Tillman to provide a spark defensively.

He did just that and then some.

In 11 minutes of playing time, Tillman blocked two Luke Doncic shots, collected four rebounds and hit a wide-open corner 3-pointer late in the third quarter to put the Celtics up 13.

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Jaylen Brown was driving the lane when Maxi Kleber left Tillman to help Daniel Gafford on defense. With Brown pulling the double team, he kicked the ball out to Tillman.

"I knew that when I saw Maxi Kleber go to the block, that I was going to shoot regardless of anything. And then their bench was talking," Tillman said after the Celtics 106-99 win, per league-provided transcript. "And then their bench was talking. So, it was cool to hit it and be able to look at the bench as well."

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Tillman flashed a smile at the Dallas bench as he ran up court.

And the Celtics bench, led by Jayson Tatum, let Tillman know the magnitude of the bucket.

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"To hear the bench going crazy on our end," Tillman said. "Guys like Svi (Mykhailiuk) and Oshae (Brissett) and stuff like that, it was pretty awesome because those are my guys. Those are my SRG (stay-ready group) guys. Each day in, day out, we go to war with each other to try to better each other, to be ready for whoever's name gets called. So for them to celebrate with me is pretty cool."

Giving Tillman minutes over Oshae Brissett, Luke Kornet or Neemias Queta may have come down to the experience he has against the Mavericks more than anything else.

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"He played in the Western Conference for three or four years, and so he's played against the Mavs. So, he's had that experience," Mazzulla said, per league-provided transcript. "... I thought with that comfort level of playing against those guys for so long, he was going to be able to execute the things that we needed to execute."

Mazzulla continued: "And so I thought he did a great job in switching and did a great job in our screening, getting into our spacing. And that's what we talk about with those guys, is regardless of who is in, who is out, I trust the next man up because of the work they put in and the staff that prepares them."

With Porzingis doing everything he can to get back in the lineup for Game 4, Tillman may not see action again in the series, but he certainly earned praise in the first NBA Finals appearance of his career.

Featured image via Peter Casey/USA TODAY Sports Images