DALLAS -- For a few minutes in the fourth quarter of Game 3 of the NBA Finals on Wednesday night, it looked like the Boston Celtics' bad habits would come back to haunt them.

The Dallas Mavericks, who appeared finished when they trailed by 21 points with 10 minutes to go, roared back with a 22-2 run, putting Boston's lead in peril and threatening to make this a series.

But just when things looked their bleakest, the Celtics flipped the script, holding Dallas to one field goal over a five-minute span, and claimed a 106-99 victory for a 3-0 series lead.

Boston is one win away from a record-setting 18th NBA championship -- one the Celtics can capture Friday in Game 4 here at American Airlines Center.

"Experience is the best teacher," said Jaylen Brown, who finished with 30 points, 8 rebounds and 8 assists in 41 minutes. "All year long we've been hearing about the Celtics are the past, for the last six to eight months, that's all we've been hearing is all the different shortcomings we've had in the past.

"This is a new team, you know what I mean. We've learned from those experiences. And in these moments, you can see that we learned from it. We stepped up to the plate, and we found a way to win."

It looked like Boston had found a way much earlier, having responded to a 25-12 spurt by the Mavericks over the opening seven minutes -- a run that saw Kyrie Irving, who finished with 35 points after combining for 28 in the two games in Boston, get going for the first time in the series. The Celtics' 79-45 burst over roughly the next 29 minutes allowed them to take a commanding 91-70 lead with 11:07 remaining.

At that point, Dallas appeared to be staring at another loss despite Boston's Kristaps Porzingis sitting out Game 3 and his status in doubt moving forward because of an unusual tendon injury in his left leg sustained in Game 2.

But just as quickly as Boston had established control, Dallas rediscovered itself. As Boston went 1-for-11 and committed three turnovers over the next 7:57, Dallas pulled to within 93-92 on an Irving layup with 3:37 remaining despite playing without Luka Doncic, who fouled out a few seconds earlier. However, things started to swing back in Boston's direction, as a Brown putback of a Jayson Tatum miss was followed by a Derrick White 3-pointer and a Tatum dunk, pushing the Celtics' lead back to six points.

"Yeah, I think just we had some turnovers, which allowed them to get out in transition," White said. "And just a couple of things that we've been doing really well, we kind of just let go of the rope for however many minutes that was. It seemed like, what, two minutes, they cut it to two, three or something.

"It happened quick, and we just settled back down. Understand it's a game of runs, and we just trust what we do."

In the past, it might have been a moment when the Celtics let go of the rope and allowed Dallas to close the game out. But Boston persevered and improved to 7-0 on the road in these playoffs. It is 21-7 on the road over the past three postseasons -- the best winning percentage over a three-year span in NBA history, breaking a tie with the 1991 to 1993 Chicago Bulls.

And the Celtics did it by getting contributions from across the board. Backup center Xavier Tillman stepped into the rotation and played 11 impactful minutes, hitting a corner 3, grabbing 4 rebounds and recording 2 blocks, including one against Doncic. Sam Hauser went 3-for-4 from 3-point range and was a game-high plus-16 off the bench after going 0-for-5 from 3 in Game 2.

And Tatum, after going 6-for-22 in Game 2, finished with 31 points, 6 rebounds and 5 assists as he and Brown combined for 61 points. The Celtics are within one victory of moving ahead of the Los Angeles Lakers for all-time league titles.

But after the Celtics were down 3-0 in the Eastern Conference finals last year and forced a Game 7 against the Miami Heat, Boston knows the job isn't done.

"Honestly, not too difficult from the standpoint of last year [when] we were down 0-3 in the conference finals, and we really felt like we were going to come back," Tatum said. "We almost did. You know, we were [my] sprained ankle away from having a real shot.

"So, you know, we are not relaxing or anything like that. You know, not even focusing on winning or Friday or whatever. However long it takes, that's our motto. However long it takes, that's what it's going to take, and nobody is not trying to relax at all."