The Celtics’ Kristaps Porzingis suddenly became a big problem in the Finals for a Mavericks team that had knocked them out.

Dallas coach Jason Kidd said before the start of the series that he didn’t think Porzingis got enough praise for his ability as a shot blocker and a guy who disrupts opponents’ shots. The seven-footer did both in his thrilling return to the court in Boston’s 107-89 win in Game One, while also providing the scoring punch (20 points in 21 minutes of action) that fueled the blowout performance. It was a full display by Boston of his abilities, which had never been fully utilized during Porzingis’ time in Dallas. “He plays his role,” Kidd said. “When you tell him to do something, he does it. He doesn’t complain about his role.” He goes out and tries to help his team win.” Moreover, he did so in his first game after being absent. “I know how to do it. That’s it, that’s it, having confidence, going out and playing, whether it’s the first round or the finals, just going out with full confidence and giving the team what I have.”

It was an acknowledgement by the Mavs that using him in a system that asked him to split time between scoring and shooting 3-pointers was not a good fit for star Luka Doncic.

“We’re judged on whether it works or not. It’s part of the business,” Kidd said. There’s also the risk that trading a player of Porzingis’ caliber could ultimately prove detrimental. In Game 1, that’s what happened, with Porzingis sparking an early 17-5 run and helping Boston jump out to a 17-point lead in the first quarter. But what he did on the defensive end throughout the game had the same effect.

Two of Porzingis’ three blocks were at the rim: one on Derrick Jones Jr. and one on Josh Green. He also blocked Kyrie Irving’s jumper. Dallas’ top big men, Daniel Gafford and Derek Lively, combined to score 10 points while shooting 4-of-4 from the field.

Porzingis’ presence in the paint also kept Irving and Doncic calm. The duo, who have shattered opponents by earning 78 passes and dunks in the pick-and-roll this postseason, Or the layup, just one such play in Game One.

“He’s been doing that his whole career. He’s a great player. He’s been great for us. We’re here because of the work he’s done,” Celtics coach Joe Mazzulla said of Porzingis.

If Porzingis continues to perform like this in conjunction with the Celtics’ other weapons, they could be too much for Dallas to handle. But the Mavericks have promised to try. “We just have to be better. We know that,” Kidd said. “Boston is a really good team and so we have to be better on Sunday.