Jaylen Brown was frustrated by the way the Boston Celtics gave the Atlanta Hawks "life" in Game 5, passing up a "tremendous opportunity" to clinch their first-round playoff series.

The Celtics were 3-1 up heading into Tuesday's game in Boston, but they now must go on the road again to attempt to finish the job in Atlanta.

That is after the Hawks won 119-117 in perhaps the biggest upset of the postseason so far.

Dejounte Murray was missing for the Hawks, serving a one-game suspension, but All-Star team-mate Trae Young finished with 38 points and 13 assists in a dominant performance.

"We had a tremendous opportunity," Brown said. "We controlled the game for the most part, and then Trae Young just put on a hell of a performance in the fourth quarter."

Indeed, Young had 16 points in the fourth quarter, including each of the Hawks' last 14.

Atlanta outscored Boston by 12 points in the fourth, having still trailed by eight entering the final four minutes before Young took over, hitting a 30-foot, game-winning three over Brown with three seconds left.

"We made some bonehead plays, some fouls," Brown added. "We gave them some opportunities to get going. We've just got to finish the game.

"We let the game get away from us a little bit, and they just hit shot after shot down the line. When you give a team life, you give them a chance, and that's what we did."