Jaylen Brown scored 25 points as the Boston Celtics recovered from a poor first half to win at the Miami Heat and move within one win of the NBA Finals.
After trailing 42-37 at half-time, Boston won 93-80 in Miami to take a 3-2 lead in the Eastern Conference finals.
Jayson Tatum added 22 points and 12 rebounds for the Celtics, who are aiming to reach the NBA Finals for the first time since 2010.
Boston host game six of the best-of-seven series on Friday.
Bam Adebayo produced 18 points and 10 rebounds for the Heat, who lost at home for the second time in the series after going 6-0 in Miami during the opening two rounds of the play-offs.
Boston took charge in the third quarter, outscoring Miami 32-16, and they opened their first double-digit lead on a Brown turnaround jumper with eight seconds remaining in the quarter to lead 69-58.
Then in the fourth quarter, Brown hit consecutive three-pointers to cap a 24-2 run and give Boston an 83-60 lead.
The Golden State Warriors host the Dallas Mavericks in the Western Conference play-offs on Thursday, leading 3-1 and knowing victory will see them reach the Finals for the first time in three years.