Tatum scored 31 points and Brown 30 as the Celtics won 106-99 in game three of the best-of-seven series.

The Mavericks reduced their deficit from 91-70 early in the fourth quarter to one point with three and a half minutes left but failed to turn an impressive comeback into a victory.

Kyrie Irving scored a game-high 35 for Dallas, while team-mate Luka Doncic contributed 27 but fouled out of the game with just over four minutes remaining.

Boston are one win away from an 18th NBA title and first since 2008, with the next game on Saturday (01:30 BST).

“We are not relaxing or anything like that,” said Tatum. “You know, not even focusing on winning or whatever.

“However long it takes, that’s our motto. However long it takes, that’s what it’s going to take. Nobody is not trying to relax at all.”

Brown added: “That was a big-time win for us, and I’m proud of how we played.

“They had some momentum, but we kept our poise. We made timely baskets.

“We got some good shots going in, and we found a way to win.”

The Mavericks will have to make history if they are to claim the NBA title as no team has ever recovered to win from 3-0 down to win a play-off series.

“It’s not over till it’s over,” said Doncic. “We’ve just got to believe.

“Like I always say, it’s first to four. We’re going to stay together. We lose together, we win together.”

Boston had a 15-point lead cut to two with less than two minutes remaining but dug in to extend their lead at the top of the Eastern Conference.

Tatum was one assist shy of a triple-double as he finished with 26 points, 10 rebounds and nine assists.

Kristaps Porzingis added 25 points while Tyler Herro scored 24 for Miami.

Boston star Jaylen Brown and Miami’s Duncan Robinson clashed in the fourth period and exchanged heated words before Brown was assessed a flagrant foul.

A three-pointer from Herro then got Miami – who shocked the Celtics in last year’s Eastern Conference Finals – back to within two at 106-104 with 1:49 remaining but Tatum and Porzingis sealed the win from the free-throw line.

Elsewhere, Shai Gilgeous-Alexander exploded for 38 points and Jalen Williams added 32 as the Oklahoma City Thunder beat the Sacramento Kings 127-113.

The win ended a two-game losing streak for the Thunder and moves them up to third in the Western Conference, half a game back from leaders the Minnesota Timberwolves.

The Kings, for whom center Domantas Sabonis had a triple-double of 21 points, 11 rebounds and 14 assists, stay in the play-in places as they sit seventh in the West.

Jayson Tatum scored a game-high 45 points, including 12 in overtime, with Jaylen Brown chipping in with 35 points and 11 rebounds.

The Celtics have won 18 games in a row at TD Garden.

Boston (29-8) lead the way in the Eastern Conference with Minnesota (26-11) top of the Western Conference.

Elsewhere, the San Antonio Spurs ran out comfortable 130-108 winners against the Detroit Pistons.

Spurs’ Victor Wembanyama registered the second-fastest triple-double in NBA history as he scored 16 points, 12 rebounds and 10 assists in just 21 minutes.

It is the 34th defeat in the past 35 games for Detroit and their sixth straight loss.

Jalen Johnson caught the eye for the Atlanta Hawks, scoring 25 points – seven of them in overtime – with a career-high 16 rebounds to lead his side to a 139-132 win against the Philadelphia 76ers.

The Sixers have lost three in a row but remain third in the Eastern Conference, while the Hawks are 11th.

The Indiana Pacers ran out 112-104 winners against the Washington Wizards with Myles Turner scoring 18 points and 13 rebounds, while the Sacramento Kings made it back-to-back wins with a 123-98 victory against the Charlotte Hornets.

It was also a successful night for the Oklahoma City Thunder when they travelled to the Miami Heat, winning 128-120 as Shai Gilgeous-Alexander scored 28 points.

The Chicago Bulls recorded their second successive win in overtime when edging past the Houston Rockets 124-119.

The Golden State Warriors’ form continues to be a major issue as they slumped to a sixth loss in eight games when suffering a heavy 141-105 defeat at home against the New Orleans Pelicans.