His points haul includes a 26-foot 3-point shot that capped a 13-3 Celtics run to start the fourth quarter, and gave them the biggest lead of the game.
The Celtics were led by their star guard Isaiah Thomas with 29 points and a game-high 12 assists.
The Celtics overcame a playoff career-high 38 points from Wizards guard Bradley Beal.
All jokes aside, both the Eastern Conference finals and the Western Conference finals look pretty much exactly as they were expected to: the Celtics and the Cleveland Cavaliers in the East and the Golden State Warriors and San Antonio Spurs in the West.
The Celtics had the largest lead of the first half at 10-2, but that gap was quickly erased by Washington as Boston started to rack up fouls. Bojan Bogdanovic was the only Wizards reserve to score, and he was a minus-19 in 16 minutes.
"I think the bench was a big factor in Game 5 (a Boston win at home) and Game 7 certainly was as well", Celtics coach Brad Stevens said.
BOSTON (AP) - Isaiah Thomas said he didn't feel any pressure entering the first Game 7 of his career. The series, though, got chippy after Kelly Olynyk popped out Kevin Love's shoulder while battling for a rebound in Game 1.
That could be a crucial turning point in what otherwise was looking to be another potential seven-game series in the conference finals.
Game 1: Wednesday, May 17 at Boston, 8:30p.m.
Severe Storms And Tornadoes Possible In Nation's Midsection
More thunderstorms moving east-southeast out of Iowa will be moving into southern Wisconsin and northern IL later this evening. The best chance for storms on Saturday will be in the morning with more isolated storms by the afternoon if not dry.
Bradley Beal was sensational in the second half, finishing with 24 points on 9-of-14 shooting.
For the Wizards, they should be proud of their season. We played them four times.
While Boston's Olynyk, Smart, rookie Jaylen Brown and Terry Rozier all made significant contributions in Game 7, Washington's cast of Mahinmi, midseason acquisition Brandon Jennings and Jason Smith put up the goose egg, and Kelly Oubre Jr. saw the floor for just six seconds after being a factor earlier in the series. Celtics vs Wizards live streaming, 2017 NBA Playoffs live streaming and Game 7 live streaming info follows. He scored 11 of 13 points for Boston as the Celtics pushed their lead to 110-100.
During the regular season, the Cavaliers won three of their four games against the Celtics, including a 114-91 victory at TD Garden on April 5.
Celtics were more aggressive on the boards as their 43-31 advantage showed, and while the Wizards were sloppier with the ball committing 15 turnovers, the hosts limited their turnovers to just eight, the first time in the series either of the teams recorded a single digit in that category.
Monday's victor earns an Eastern Conference finals matchup with the defending champion Cleveland Cavaliers, who have been awaiting an opponent since sweeping Toronto on May 7. But the true hero was Kelly Olynyk.
Game 4: Tuesday, May 23, at Cleveland, 8:30 p.m.
Gortat said the Celtics need to find additional ways to win against Cleveland.
The Wizards have tried to make scoring hard for Thomas, sending two players - sometimes three - to prevent him from shooting. The Celtics sliced up this lineup, building a comfortable lead that could withstand Beal's second run.