BOSTON — If the rest of the league has one regret through two games of the NBA Finals, it is a question the Milwaukee Bucks must ask themselves daily: How did we let the Boston Celtics acquire Jrue Holiday?

He was available from the Portland Trail Blazers for a moment, when the Bucks discarded him in favor of Damian Lillard, and the Celtics pounced, dealing Malcolm Brogdon, Robert Williams III and a pair of first-round draft picks on training camp's eve. Nine months later, Holiday is a leading Finals MVP candidate.

Two days from his 34th birthday, Holiday logged team highs of 26 points and 11 rebounds Sunday night. He made 11 of his 14 shots. Defensively, he drew Kyrie Irving and Luka Dončić late, wearing down both. He did it all in a 105-98 win against the Dallas Mavericks in Game 2 of the NBA Finals, staking Boston to a 2-0 series lead.

"I credit the victory to him tonight," Celtics teammate Jaylen Brown said.

Jayson Tatum was the first to welcome Holiday onto a team that had reached this stage two years earlier. Everyone else soon followed suit. All the Celtics credit Holiday's selflessness — his willingness to accept a role smaller than his stature — for setting a tone that permeates the locker room. Winning over anything.

"He could easily have come in and been like, 'I'm Jrue Holiday,'" said Celtics teammate Derrick White, who delivered Sunday's game-saving block, "and I would've been like, 'Yeah, you are Jrue Holiday — 100%.'"

Instead, there was no ego, and in its place are championship habits. Holiday was Milwaukee's point guard and primary ball stopper on a title team. In Boston, he leaves the point guard duties to White. He defers to Tatum and Brown, whom he calls "superstars." He takes a backseat to Kristaps Porziņģis on some nights. Defensively, he guards every position, much like Marcus Smart, the man he ultimately replaced in Boston.

"I think when you sacrifice together and you do something together," said Holiday, "it brings you closer."

Again: How did every other team in the NBA let that happen? The Philadelphia 76ers and Los Angeles Clippers were among the chief competitors for Holiday's services, and both would have benefited greatly from his presence. No one in Boston wanted to see him land on the Miami Heat. Every contender needed Jrue Holiday, and not one of them prevented him from joining a Celtics team that needed exactly him.

"Jrue is a great teammate, nothing short of that," said Brown. "He's brought championship pedigree to our team. So nothing Jrue says we question. He just is who he is. He's got that demeanor, that killer-like mentality, and we respect it. He's a great teammate, and it's just an honor to play next to him."

What that looked like in Game 2 was smart basketball — Jrue Holiday basketball. The Mavericks tried to hide Irving on Holiday, so the Celtics guard led him to the dunker's spot. There he amplified the offense twofold. Irving could not protect the rim as a help defender, and Holiday feasted on feeds from Tatum. Six of Tatum's game-high 12 assists found Holiday for 13 of his 26 points. This is how the Celtics made a game out of a night they missed their first eight 3-point attempts and finished 10-of-39 from distance.

"I know that sometimes when I drive and I might get stuck, I need somebody to drift with me or to kind of be in space and be in my vision," Holiday said, describing how he plays off Tatum. "So I think for the most part, I just try to stay in front of him, give him a good outlet. He's been making great reads."

Well, that and a defense that held Dallas to 70 points over the final three quarters. Holiday has now guarded Irving and Dončić for 15 minutes of this series, per the NBA's tracking data. They have scored 13 points on 13 shots in that span, and the Mavs are scoring 84 points per 100 possessions — essentially the worst offense in modern NBA history — whenever Holiday is defending one of their two best players.

"That experience, that just championship DNA, which you hear about all the time," White said, effusive in his praise of Holiday. "You don't really know what it takes until you do what it takes. The moment he came to our team in training camp, he kind of had that presence about him. He just knows how to win."

If there was one sequence on Sunday to sum up what Holiday means to the Celtics, it is this:

The Mavericks had an opportunity to cut into Boston's eight-point lead with four minutes to play. Holiday, defending Dallas forward P.J. Washington, deflected a pass in the backcourt. He shifted onto Dončić, who had only a moment to avoid an eight-second violation. Holiday forced a bad pass, which White picked off, returning to Holiday, who delivered a 3-point dagger. On the next possession, Holiday forced an Irving miss, grabbed an offensive rebound on the other end and found White for another 3.

The game was all but over, and the Mavericks hardly knew what hit them. It was Holiday. He hit them — repeatedly. With crafty layup after crafty layup, a pair of 3s, three assists, a block, a steal, a bit of it all.

This is what Jrue Holiday does, some of everything, and it is all a luxury to a team that had no idea he would even become available until the dawn of preseason. What would these Celtics be without Holiday?

"Good thing we don't have to find out," said Tatum. "We're very, very fortunate to have him."