Boston’s Jayson Tatum drives against Toronto’s Pascal Siakam during the second half of Game 7 of their conference semifinal series on Friday in Lake Buena Vista, Fla. Mark J. Terrill/Associated Press

LAKE BUENA VISTA, Fla. — It took every bit of seven games, but Jayson Tatum and the Boston Celtics are headed to the Eastern Conference finals.

And they dethroned the NBA champions to get there.

Toronto Coach Nick Nurse, left, and Boston’s Daniel Theis react during the second half of Friday’s Game 7 in Lake Buena Vista, Fla. Mark J. Terrill/Associated Press

Tatum scored 29 points, Jaylen Brown had 21 and the Celtics topped the Toronto Raptors 92-87 on Friday night in Game 7 of the East semifinal series.

Marcus Smart scored 16 points and Kemba Walker added 14 for third-seeded Boston. The Celtics will face the fifth-seeded Miami Heat in the East finals.

Fred VanVleet scored 20 points for Toronto, which got 16 from Kyle Lowry, 14 from Serge Ibaka, 13 from Pascal Siakam and 11 from Norman Powell. The Raptors were bidding to become the seventh franchise in NBA history to win four consecutive Game 7’s.

Boston scored the first seven points of the fourth, taking an eight-point lead. The Celtics never trailed in the final quarter, though it was close all the way to the end.

Powell had a chance to tie it on a drive with just under a minute left, his layup erased by Smart with a block that preserved an 89-87 lead. Lowry fouled out on the next possession, a call the Raptors argued and challenged to no avail. Grant Williams missed both free throws, but Powell fouled Tatum going for the rebound.

Tatum made one of two, the lead was three and all Boston needed was one more stop.

The Celtics got just that; VanVleet was well short on a 3-point try, Kemba Walker sealed it with free throws with 7.9 seconds left, and Toronto’s reign was about to end.

It was exactly one year ago Friday when four Celtics – Walker, Smart, Brown and Tatum – were part of the USA Basketball team in China that fell apart in the fourth quarter of a Basketball World Cup quarterfinal against France, a loss that kept the Americans out of the Final Four of that tournament.

Not this time. Not this year.

Next week, there will be four NBA teams left standing. The Celtics will be one of them.

The chess match started from tipoff.

The Raptors started in a box-and-one on Walker, so the Celtics quickly subbed out Daniel Theis for Robert Williams early to get some more athleticism on the floor – and Boston quickly put together what became a 13-0 run on the way to an early 19-7 edge.

Toronto made the next adjustment, trotting out a lineup to end the first quarter that the Celtics hadn’t seen yet and promptly going on a 10-0 run. The Raptors eventually led by as many as seven; Boston then went on a 15-2 spurt to reclaim the lead and the Celtics ended up taking a 50-46 lead into the break.

The back-and-forth continued in the third. Boston pushed the lead to nine, Toronto scored the next eight, eventually took the lead before the Celtics claimed it back.

Boston led 72-71 going into the fourth, making this the 21st Game 7 in NBA history where the margin was zero or one points going into the final 12 minutes.

RARE MATCHUP

This will be the first time neither the No. 1 nor No. 2 seed in the East will make the conference finals since the NBA went to the 16-team playoff format in 1984; this one will feature No. 3 Boston and No. 5 Miami.

There have been similar matchups in the West since the league went to this format. No. 3 Dallas beat No. 4 Oklahoma City in 2011, No. 3 San Antonio beat No. 4 Utah in 2007 and No. 3 Portland beat No. 5 Phoenix in 1990.

The last time something like this happened in the East was 1969, when No. 4 Boston beat No. 3 New York in what was then the Eastern Division finals.

NOTES: Gordon Hayward (sprained right ankle) was on the floor getting shots up before the game. He hasn’t played since Game 1 of the opening-round series against Philadelphia. The Celtics had said he would need four weeks before recovering; Tuesday is the four-week mark. … Toronto was eliminated 456 days after winning the preceding season’s title, obviously the longest such run for a team that didn’t win consecutive championships. … The Celtics went 2-1 against Miami in the regular season, winning 112-93 on Dec. 4 in Boston and 109-101 at Miami on Jan. 28. The Heat won the lone bubble matchup between the clubs, prevailing 112-106 on Aug. 4.