The Boston Celtics beat the Indiana Pacers 133-128 in overtime (OT) in Game 1 of the NBA Eastern Conference Finals at TD Garden in Boston, Massachusetts, on Tuesday, leading 1-0 in the series.

The Pacers had the chance to win on the road during regular time, as they led by three points (117-114) when there were 39.1 seconds left. Jayson Tatum missed a 3-pointer from the top of the key. Tyrese Haliburton mis-dribbled and gave the ball possession back to the Celtics. Derrick White charged toward the rim but his layup ended a brick. Neither did Tatum's putback attempt go into the hoop.

The Pacers then made more mistakes. Pascal Siakam failed to receive the inbound pass due to the deflection by Jaylen Brown. The ball flew out of the baseline after Siakam touched it last, giving the Celtics another chance to save the game. Jrue Holiday passed the ball to Brown in the left corner. The Pacers, or, more specifically, Siakam, had the chance to foul him so he could only shoot two free throws. He could also close out to keep Brown from shooting a triple even at the cost of allowing an open 2-point field goal (FG). Since there were only 8.5 seconds left, the Pacers could live with that.

However, Siakam did neither. Instead, he watched Brown shoot and make a significant 3-pointer that tied the score for the Celtics. The Pacers called a timeout for coach Rick Carlisle to draw a play for the final 5.7 seconds in the fourth period. Haliburton received the ball, but he was held by Tatum before taking a poor shot and missed it.

The Celtics dominated the Pacers during OT. Tatum scored 10 points, making up for his poor work by going 2-for-7 from the field in the fourth quarter. Haliburton drew a 3-point foul in OT and made all three free throws. Nonetheless, he dribbled out of bounds again at 1:02 when the Pacers trailed by only one point (124-123).

Turnover was one of the main reasons behind the Pacers' loss on Tuesday. The whole team committed 21 of them, which the Celtics exploited to score 32 points. Coach Carlisle used an eight-player rotation each of whom played more than 15 minutes on the court. Each of them had at least one turnover. Though only three of them were at the hands of Haliburton, two of those mistakes were decisive to the result of the game.

Despite the win, the Celtics had a lot to learn from Tuesday's game. For example, their backup unit was outscored by the Pacers' counterpart 30-13. Coach Joe Mazzulla's wavering defensive plan between switching and dropping cost his side heavily in the second half. Both Al Horford and Luke Kornet became walking targets in the eyes of the Pacers' guards from the third period. Despite their incredible performance, Holiday and White found themselves vulnerable when they had to guard the much bigger Siakam and Obi Toppin next to the rim.

Game 2 of the series will be at TD Garden on Thursday.