Updated

LeBron James put the Miami Heat on his back in a game-changing -- and potential series-defining -- third quarter.

A testy Game 5 was tight before James scored 16 of his game-high 30 points in the third frame, carrying Miami to a 90-79 victory over the Indiana Pacers for a 3-2 lead in an unpredictable Eastern Conference finals.

The Heat outscored Indiana by a 30-13 margin in the 12 minutes after halftime, and the defending champions cruised down the stretch to put themselves one win away from reaching the NBA Finals for a third straight year.

Udonis Haslem stepped up with 16 points on 8-of-9 shooting and Mario Chalmers netted 12 for Miami, which forced 18 turnovers to overcome below-average production from Dwyane Wade and Chris Bosh.

"They are one of the best teams that this league has ever seen," Pacers head coach Frank Vogel said. "(But) we have a great deal of belief we can win this series. Our backs are against the wall...and it's up to us to go out and win Game 6."

Paul George finished with 27 points, 11 rebounds and five assists to lead the Pacers, whose season will be on the line at home in Game 6 on Saturday.

The Pacers had owned the battle on the glass the first four games of the series but pulled down just one more rebound Thursday (33-32), with Roy Hibbert grabbing only six to go with 22 points.

Indiana, after shooting 51 percent from the floor in the first half, made just three field goals in the third quarter. Their last bucket was a jumper from George that gave them a 53-51 edge with 5:33 remaining, which coincidentally was the last time they held the lead.

Miami scored 16 of the next 18 points to pull away. James netted seven during the surge while Haslem capped the three-minute swing with three consecutive baseline jumpers from the same spot.

Haslem's final basket came as a result of James commanding multiple defenders in the lane and dishing back outside for an open jumper and a 67-55 Heat cushion.

"That's LeBron showing his greatness and making it look easy," Heat head coach Erik Spoelstra said of the league MVP. "He was tireless (in the third quarter). He covered so much ground defensively and made virtually every play for us offensively."

A 3-pointer by George and a Tyler Hansbrough layup to start the fourth pulled the Pacers within 70-62, but they never got closer than eight the rest of the way.

George and Hibbert combined for all 23 of Indiana's points in the first quarter, with the former hitting a late 3-pointer to cap his 13-point frame and give the Pacers a 23-19 lead.

Tempers flared early in the second when Miami's Chris Andersen lowered his shoulder into an unsuspecting Tyler Hansbrough following a made basket. The blow sent Hansbrough to the floor, and the two bumped chests before an Andersen shove resulted in a Flagrant 1 foul.

Andersen blocked Hansbrough on the ensuing possession, but the Heat did not capitalize on the momentum and went into the locker room trailing by a 44-40 margin.

Game Notes

Hansbrough twisted his right ankle early in the fourth quarter and did not return ... David West scored 17 points and was hit with a technical foul midway through the third quarter when he got in a heated argument with Chalmers and Haslem, who were each even technicals as well ... The Pacers are 10-2 this postseason when leading at halftime, with both losses coming in this series ... Indiana's starting backcourt of Lance Stephenson and George Hill combined for five points on 2-of-11 shooting ... Wade and Bosh scored 10 and seven points, respectively ... The Heat outscored the Pacers in the paint, 34-32 ... Andersen hit both of his field goal attempts and is 15-of-15 from the field in the series ... Before the game, the NBA fined James, West and Stephenson $5,000 each for flopping in Game 4.