The Irish have finally clinched their second straight Scottish Premiership title with a thrilling win over the Luton Town side.
James Weir scored twice and Jack Russell provided the assist as Celtic went top.
With two wins from three, it was the first time they had won the Premiership since 2005, and the first in 17 years.
Scottish Premiership winners:Celtic v Luton – 20 February 2018 Celtic (3rd place)Luton Town (2nd place)Celtics (1st)Aberdeen (2)Preston North End (1)Glasgow Warriors (1)*Glasnevin City (1*)Glasco Rovers (1*)Portsmouth (1A)*Bristol City (0)*Rangers (0*)*Cardiff City (4)*Burnley (4)*Tottenham Hotspur (0)*West Bromwich Albion (1The result means Celtic are currently top of the table, but the team’s performance against Luton meant they could only secure a place in the top six by winning.
After the draw with Dundee United on Tuesday, Luton manager James Weir said the side was focused on the challenge ahead of their next home game.
The result was a huge step for us and a step up for us, he said.
We have had a difficult run of fixtures in the league, but it is the end of a season and we have to focus on the league.
We can’t think about the next game because we are in the last eight and we want to go back to the Championship.
The visitors, who had been chasing the Premiership title for six years, had struggled to find form in recent months and it appeared to have taken its toll on their squad.
The win will give Celtic hope of avoiding relegation, but they still face a battle to retain the top-flight title.
Luton had won four of their last five league games against Celtic, including a 5-1 thrashing in the play-off final.
The defeat was a big blow to the sides hopes of securing a top-four finish, but Weir said they were determined to go on.
He said:It is a great club and a great team, but we know we are not there yet.
We are going to do everything we can to keep going and win the league and we will keep working hard to get there.
The Scottish Premiership will now be decided by points.