Kawhi Leonard scored 36 points as the Toronto Raptors beat defending champions the Golden State Warriors 105-92, leaving them one win away from their first NBA championship.
A sensational second half from the Raptors gives them a 3-1 series lead.
The only team to overcome the same deficit in the Finals were the Cleveland Cavaliers, who beat the Warriors in 2016.
Game five of the best-of-seven series is in Toronto on Monday.
The Raptors are now on the brink of history, aiming for their first title in the franchise's 24-season history, while the Warriors are looking to claim their third consecutive title and fourth in the past five seasons.
"[We have] Just [got to] be patient, come in focused and ready to play defence and make some shots," Leonard, who added 12 rebounds, two assists and four steals to his 36 points, said. "As long as we win, I'm satisfied."
Serge Ibaka came off the bench to score 20 points and Pascal Siakam added 19 for the Raptors.
"Kawhi's two big threes to start the half really, I thought, changed the whole feel for everybody," Raptors coach Nick Nurse said.
"I just thought everybody was like, 'OK, we know we are here, let's go'. And we just kind of kept going from those two threes."
The Warriors led 46-42 going into half-time, but the visitors dominated in the third quarter to outscore the back-to-back defending champions 37-21, with Steve Kerr's side missing seven free throws and making less than 30% of their three-point attempts on the night.
After a playoff career-high 47 points in game three, Warriors guard Stephen Curry struggled on Friday, shooting nine out of 22 from the field and making just two of his nine three-point attempts.
"You just try to win one game," Warriors coach Steve Kerr, who has guided his team to three of the past four NBA championships, said.
"That's what we did a few years ago against OKC. Win one game and then move forward.
"So that's our focus now. We'll fly to Toronto tomorrow and take a look at the film, see what we can do better and try to win a game.
"We have won a lot of games over the years, so we'll try to win another one."
Warriors guard Klay Thompson was back in contention after missing game three with a left hamstring strain, and reserve forward Kevon Looney returned after previously being declared out for the series due to a chest injury.
Play-off scoring leader Kevin Durant was still sidelined, as he continues to recover from a right calf injury.
Leonard opened the second half with back-to-back three-pointers, giving the Raptors their first lead at 48-46.
The Raptors entered the fourth quarter with a 79-67 lead, with Raptors' Fred VanVleet opening the scoring with a three-pointer.
Moments later, VanVleet was taken to the locker room and needed seven stitches after an injury under his right eye when he was struck by the left elbow of Warriors' Shaun Livingston under the basket, knocking out one of his teeth.
The Warriors pulled it back to 97-89 with 2:56 remaining on the clock but failed to impress in front of their home crowd.
The loss marked what could potentially be the Warriors' final home game at the Oracle Arena in Oakland, California.
The reigning champions will only return to their base, where they have played since the 1971-72 season, should they win on Monday in Toronto and force game six on 13 June.
The Warriors move to the new Chase Center in San Francisco next season.