By JIMMY GOLEN AP Sports Writer

 BOSTON  — The Boston Celtics’ catastrophic performance in Game 4 of the NBA Finals gave them a chance to clinch another championship on Monday night under the 17 banners already hanging in the TD Garden rafters.

And, coach Joe Mazzulla reminded them, that they would still have two more chances after that.

“We don’t like to lose,” Celtics guard Jaylen Brown said before practice on Sunday. “I think we are ready for Game 5. I think that’s the best answer that I’ve got. I think that we’re ready. We’re at home. And we’re looking forward to it.”

The Celtics cruised through the regular season with the best record in the NBA and then did even better in the playoffs, never trailing in a series while winning 15 of their first 17 games. They opened a 3-0 lead on Dallas, but the Mavericks avoided elimination with a 122-84 victory on Friday night — the third-biggest blowout in Finals history.

That sent the series back to Boston, where the Celtics will again try to win their unprecedented 18th NBA title — and their first since 2008. In a city that’s collected 12 championships already this century, that’s what passes for a drought.

“This is what we all work for,” Brown said. “We are at the precipice of completing what we set out to do at the beginning of the season. So I think it’s not difficult to get everybody in that locker room on the same page right now.”

The Game 4 loss snapped Boston’s franchise-record 10-game postseason winning streak (and also ended Kyrie Irving’s personal 13-game losing streak against his former team). Boston had been 3-0 in potential elimination games so far during these playoffs.

But the Celtics know — and Dallas surely does as well — that they still have three more chances to close out the series. All-Star Jayson Tatum said Mazzulla told his team on Sunday not to “surrender to that idea that we have to win tomorrow.”

While it’s unusual for a coach to diverge from the “one game at a time” mentality, the Celtics said the acknowledgement that they have three tries to win one game takes some of the pressure off them — pressure that may have gotten to them in their total dud of a Game 4.

“We would love to win tomorrow — more than anything,” Tatum said. “But if it doesn’t happen, it’s not the end of the world. We have more opportunities.”

Irving said that the Mavericks are also trying to “enjoy the moment” and not focus on the fact that no NBA team has ever come back from a 3-0 deficit in a playoff series. Game 6 would be back in Dallas on Thursday, with the potential deciding Game 7 in Boston on Sunday.

“(We are) just thinking about the goal that we have in front of us as best we can, and try not to get tired of everyone talking about the history that has not been made,” Irving said. “We got a chance to accomplish one of our goals, which is to make it back to Boston. We have another goal in front of us, and that’s to make it back to Dallas.”

That will be a lot harder if Boston center Kristaps Porzingis is available. The 7-foot-2 Latvian was listed on Sunday as questionable with a dislocated tendon in his left ankle.

Porzingis did not speak to reporters on Sunday. He practiced with the team wearing a white sleeve on his right leg, and during the 30 minutes that reporters were able to observe him on the court he was gingerly putting up shots from inside the lane, apparently taking care not to jump.

“I’m not sure where he’s at,” Mazzulla said. “But he’s trying and doing everything he can to try to put himself in position to be out there. I know that for sure.”

Porzingis missed 10 straight playoff games after straining his right calf in the first-round series against Miami. He returned for Game 1 of the finals and was a big reason for Boston’s victory, scoring 20 points with six rebounds and three blocked shots in 21 minutes.

But Porzingis dislocated a tendon in his left leg in Game 2, did not play in Game 3 and was said to be available for Game 4 “on a specific basis, if needed.” (With the Celtics quickly falling behind in a 38-point loss, he never checked into the game.)

Less of a concern is the status of Mavericks star Luka Doncic, who has been on the injury report with injuries to his right knee and left ankle along with a bruised chest. He went through the warmups for Game 2 with his torso and knee wrapped, but delivered a triple double in the loss.

“At this point in the season, a lot of things going on,” he said on Sunday. “If I’m playing, I’m fine. No worries.”