The Celtics’ journey to Las Vegas came to an end on Monday night in Indianapolis when they lost to the Pacers, 122-112, in the NBA’s first-ever in-season tournament’s knockout stage.

Now that the Celtics are out of the postseason, Boston will play a regular-season game on Friday night against the Knicks or Bucks. Whoever emerges victorious from Tuesday’s elimination match between New York and Milwaukee will be their opponent.

With the victory, the Pacers move on to the in-season tournament semifinals, where they will play the Knicks/Bucks winner at T-Mobile Arena in Las Vegas on Thursday.

After defeating the Bulls handily on November 28 to win East Group C, Boston secured its ticket to the tournament’s quarterfinals.

The Nets’ victory against the Raptors by fewer than 19 points that same evening and the Celtics’ passage to the knockout round were the only things that cleared the way for them last week.

However, in a boisterous Gainbridge Fieldhouse, the Celtics’ luck ran out against the Pacers.

Tyrese Haliburton and the Pacers were too much for the Celtics to contain in the second half, as they scored 72 points in the last two-quarters of play to secure the comeback victory. The Pacers had a 55-48 advantage at the break.

Jaylen Brown contributed 30 points and nine rebounds, while Jayson Tatum ended with 32 points, 12 rebounds, and six assists. Haliburton scored 26 points, pulled down 10 rebounds, and disheveled 13 assists to lead the Pacers.