NEW YORK -- Heading into Friday night's Game 6, it would have been understandable for there to be questions about the New York Knicks' ability to shut the door on the Boston Celtics.

After all, the Knicks suffered a 22-point Game 3 defeat after a pair of improbable 20-point road comeback victories, with captain Jalen Brunson acknowledging New York might have gone into that contest "subconsciously satisfied" because of its unexpected series lead. Similarly, when the Knicks took a 3-1 series lead into Boston for Game 5 after Jayson Tatum's Achilles rupture, they faltered badly in that closeout opportunity and were routed by the short-handed Celtics.

It all raised the possibility of a high-pressure Game 7 in Boston if the Knicks couldn't handle business Friday night.

But New York emphatically quashed that question -- and the defending champion Celtics' slim chances of a repeat -- in a thorough 119-81 victory to win the second-round series at Madison Square Garden and advance to the Eastern Conference finals for the first time since 2000. The Knicks will host the Indiana Pacers, who knocked them out of last year's playoffs in Game 7 of the conference semifinals, starting Wednesday night in New York.

Knicks fans, euphoric over the win, poured into the streets surrounding the Garden, with some climbing light poles and standing on top of taxi stands along Eighth Avenue.

After a 25-point shellacking in Game 5, the Knicks' 38-point win marked the largest margin of victory in franchise postseason history.

"We watched the film, and we were kind of disgusted with our communication, our effort and our sense of urgency," Josh Hart said of Gams 5 after finishing Game 6 with 24 points, 11 rebounds and 11 assists. "That was something we knew we had to fix."

Coach Tom Thibodeau and multiple players repeatedly said New York had yet to piece together a playoff game with solid defensive effort, focus and ball movement for 48 minutes. But the Knicks brought it all Friday.

Asked if this was his team's best postseason showing, Thibodeau thought for a moment before answering.

"Probably," he said. "I thought from start to finish that we were terrific."

No stretch of the game stood out more than the second quarter, when New York outscored Boston 38-17 and took a 27-point lead at the half.

In one of the defining plays of that quarter, Celtics guard Derrick White stepped in front of a pass from OG Anunoby and dribbled to the other end of the floor for what figured to be a layup. But Knicks guard Deuce McBride chased down White and pinned his shot against the backboard, sending the Garden into a frenzy.

With the crowd still on its feet because of the block, Hart grabbed the loose ball and began a fast break, eventually hitting a floater while getting fouled by Boston's Jrue Holiday. Hart hit the free throw to cap the five-point swing for the Knicks in a game where the Celtics -- without Tatum, and with Kristaps Porzingis again struggling physically -- had no margin for error.

That didn't stop Jaylen Brown and his Boston teammates from making miscues. The Celtics had six turnovers in the second quarter -- matching their six field goals during that period -- and gave up 15 offensive rebounds in the game. Brown, Boston's high scorer with 20 points, fouled out late in the third quarter and was serenaded to Ray Charles' "Hit the Road Jack" by the Garden crowd as he walked to the Celtics' bench to end his season.

Four New York players -- Brunson, Hart, Anunoby and Karl-Anthony Towns -- finished with at least 20 points.

During the team's postgame news conference, four of the starters answered questions together -- perhaps to signify the collective win.

They were asked whether they understood the joy they injected into the city, and if they were aware of how long it had been since the club had gotten this far. And after a while, when the players continued to answer the questions in a straightforward manner, they fielded one about whether it was too soon for them to show a sense of accomplishment.

"I just think there's still more to go. We're not done," said forward Mikal Bridges, who joined the team after being traded from the Brooklyn Nets during the offseason. "We played hard and handled business, but the season's not over yet."