Jayson Tatum had an inkling the Celtics would win Game 6 against the Bucks, and he certainly made sure of it

Jayson Tatum (left) and Jaylen Brown are congratulated after a job well done in Game 6.Jim Davis/Globe Staff

MILWAUKEE — Maybe Jayson Tatum knew something the Celtics faithful just couldn’t imagine because there was a reason for his unwavering confidence after the Game 5 collapse. It appeared as he relished the opportunity to play his best game as a Celtic, to shine in the biggest moment with the season on the brink.

It had been a tough 48 hours since the Celtics wasted a 14-point fourth-quarter lead Wednesday. Nightmares conjured a total Game 6 collapse, a 40-point loss with the Celtics completely imploding and ruining what has been a renaissance season.

Tatum quickly erased those dreary visions by not only scoring 18 first-half points to give the Celtics a double-digit lead but also carrying his team and preventing another Milwaukee rally in the fourth with brilliant shot-making.

In the biggest game of his career, Tatum delivered his best performance, saving the Celtics season with 46 points, 16 in the final period, to lift Boston to a 108-95 win Friday at Fiserv Forum.

Not only did the win extend the season and force a Game 7 at TD Garden Sunday, it cemented Tatum’s status as one of the league’s elite players and rising superstars.

It was Tatum who was strangely upbeat Wednesday after one of the worst losses of his career. He still oozed with confidence, still talked with that swagger and bravado as if the series was far from over.

“That was in the back of our mind, Game 5, and that’s something that we talked about,” Tatum said. “The eagerness, we were upbeat, we weren’t defeated knowing we still had an opportunity to save our season and coming in here and get a win. We believed that. We truly did. We believed in each other and it showed tonight.”

He proved that the Celtics have learned from their past playoff miseries; the Miami series in the NBA bubble, where the Celtics were just manhandled by a less talented but harder-playing Heat.

That again was the case in Game 5, when the Bucks won with a streak of hot shooting, offensive rebounds and hustle plays, while Tatum did not record a field goal for the final 3 minutes, 40 seconds. This time, Tatum made every pivotal shot, splashing 3-pointers and more importantly, attacking the Bucks defense off the drive and scoring contested twos.

Boston took the lead with 3-point shooting Friday. It won the game with 2-point shots. In 42 minutes, 43 seconds, Tatum made 17 of his 32 shots, including seven 3-pointers, along with 9 rebounds and 4 assists. He matched the great Giannis Antetokounmpo basket for basket, burning the overwhelmed Bucks defense with his array of shots.

The Celtics desperately needed this Tatum. They needed a player who couldn’t allow his team to lose, who wanted to atone for his responsibility in that Game 5 meltdown. The Milwaukee Bucks have championship mettle, making them difficult to put away, even Friday when they sliced an 18-point deficit to 4 with 7 minutes, 48 seconds left.

Tatum responded with 10 consecutive points to increase the lead to 8 with less than six minutes left. Celtics coach Ime Udoka then called an after-the-timeout play for Jaylen Brown, who helped by draining a three for an 11-point lead.

That still wasn’t enough. When the Bucks appeared sagging and nearly done, Tatum ended the suspense with an acrobatic layup and free throw, and then another pair of free throws to close out his night and the Bucks.

“That’s why he gets paid the big bucks, that’s it right there, for moments like that,” guard Marcus Smart said. “He came in and took that game over in the fourth. He went into another mode right there. We seen it in eyes. He was aggressive. He was coming and telling us, ‘give me the ball’ and we give him the ball. We put the ball in his hands and let him create for us.”

While it was in Milwaukee, Jayson Tatum's performance Friday likely won him fans across the country.Jim Davis/Globe Staff

There have been moments throughout his career where Tatum has been brilliant, breathtaking because of the combination of his size, skill set and prowess, but never has there been a better time, a bigger time for him to show those attributes. The Bucks, one of the better defensive teams in the NBA who have frustrated Tatum at times in this series, including 4-for-19 shooting in Game 3, couldn’t guard him.

Tatum did what the greats before him — Kobe, LeBron, Jordan – have done, elevate their games when they team needs it the most. Tatum has never hidden his desire to become one of the all-time great players. He spent quality time with many of the NBA All-Time 75 players at All-Star weekend and soaked up stories, knowledge and encouragement.

He responded with the best stretch of basketball in his young career, turning into a more consistently dominant player offensively. Since that poor Game 3, Tatum is averaging 36.6 points on 40 for 85 (47 percent) shooting. And it wasn’t that he had a subpar Game 5, he did not impose his will down the stretch.

That wasn’t the case Friday, when he was the best player on the floor, even with two-time MVP Giannis Antetokounmpo single-handedly keeping the Bucks close with 44 points and 20 rebounds. Tatum was that good and now Celtics faithful know the reason he was so optimistic after Game 5.

He wasn’t going let the Celtics leave Milwaukee without atonement.