Celtics rout Mavericks to win record-setting 18th NBA championship
Humbled by Dallas in a 38-point Game 4 drubbing on Friday, Boston slammed the door on any chance of a Mavericks fightback to seal a 4-1 series victory at an electric TD Garden.
Tatum spearheaded a superb performance at both ends of the floor as Boston pulled clear of their arch-rival Los Angeles Lakers to stand alone with 18 NBA titles.
The emphatic win came 16 years to the day after Boston's last NBA Finals win - over the Lakers - in 2008.
"Oh my God. It's a surreal feeling. We did it," a jubilant Tatum exclaimed after the triumph. "We did it - oh my God, we did it!"
"This is an incredible feeling. I'm lost for words. I'm sorry."
Jaylen Brown, who was named Finals Most Valuable Player, gave Tatum scoring support with 21 points, while Jrue Holiday added 15 and Derrick White 14.
"It was a full team effort," said Brown, who averaged 20.8 points, 5.4 rebounds and 5.0 assists in five Finals games.
The defeat marked a miserable end to the finals for Dallas duo Luka Doncic and Kyrie Irving, who had led the Western Conference fifth seeds on an improbable giant-killing journey to the NBA Finals.
Doncic, sensational during the Mavs' Game 4 rout of the Celtics, finished with 28 points.
"I'm proud of every guy that stepped on the floor, all the coaches, all the people behind," defeated Doncic said afterwards.
"Obviously, we didn't win the Finals, but we did have a hell of a season and I'm proud of every one of them."
Asked what was going through his mind, Doncic replied: "Nothing. Sad we lost."
Irving frustrated
Irving scored a meagre 15 points while being taunted with chants of "Kyrie sucks!" by Celtics fans still rankled by his departure from the team in 2019.
Irving however was able take positives from the defeat, noting that Dallas boast a young core with plenty of room for improvement.
"We got to the top of the mountain and we failed, so now we have to start at the bottom, and that should be inspiring," Irving said.
"I see an opportunity for us to really build our future in a positive manner where this is almost like a regular thing for us, and we're competing for championships."
Top-seeded Boston meanwhile reasserted their superiority in convincing fashion after their Game 4 blowout, leading by double digits from late in the second quarter until the final buzzer.
The Celtics laid the foundations for victory with a controlled first-half performance that saw them open up a 67-46 lead at the break.
Payton Pritchard put the seal on a superb first two quarters for Boston, launching a mammoth buzzer-beating three-pointer from near half-court that gave the Celtics a 21-point advantage.
Boston had been swiftly into their groove early on, building a 9-2 advantage in the first quarter with their swarming defence never allowing Dallas to build any kind of rhythm.
After Boston took a 13-5 advantage the Mavs rallied to narrow the gap to two points at 17-15, but Boston's defense reclaimed the initiative soon afterwards.
Two quick steals from Tatum and Sam Hauser allowed the Celtics to pull away to 28-18 at the end of the first quarter.
Boston's defence gave no respite to Irving and Doncic, restricting Dallas's stars to just 14 points between them in the first quarter.
By contrast, Tatum and Brown threatened to over-run the Mavs defence.
There was no let-up from Boston after the restart, with Holiday's cutting layup putting Boston 26 points clear at 78-52 early in the third quarter.
There were flickers of a Dallas recovery in the latter stages of the third quarter, but Boston remained in control to lead by 19 heading into the final period.
With the TD Garden roaring them on, there was never any chance the Celtics would be denied and Boston continued to find mismatches to score freely and retain a comfortable double-digit advantage to close out the win.