The Chicago Bulls took full advantage of Kyrie Irving’s absence to romp to a 108-85 blowout against the Boston Celtics on Monday. Nikola Mirotic scored 24 points while Bobby Portis added 23 as the Bulls (6-20) stunned the Eastern Conference-leading Celtics.

Boston’s preparations had been jolted after star point guard Irving was ruled out with a thigh injury just before the game in Chicago. With forward Marcus Morris also missing with a sore left knee, the Celtics were forced to field an under-strength team just 24 hours after facing Detroit on Sunday.

The Bulls exploited Boston’s makeshift line-up to full effect, with Mirotic producing a dominant display which also included eight rebounds. It was a superb display from Mirotic and Portis, who notoriously came to blows in a practice session in October which left Mirotic with multiple facial fractures and a concussion.

The Bulls have not lost since Mirotic returned from those injuries in his season debut last Friday after missing 23 games. The Montenegrin said he and Portis had put their differences behind them to build a “great chemistry.”

“Bobby and I, we are playing good, we are finding each other and we are bringing that energy that the team needs,” Mirotic said. Bulls coach Fred Hoiberg also paid tribute to the way Portis and Mirotic had bonded.

“They’re both pros,” Hoiberg said. “I love to see the way they’re playing together. Hopefully they’ll keep it going.” Al Horford led the Boston scoring with 15 points, one of five Celtics five players in double figures.

Boston fell to 23-6 with the defeat but remain secure on top of the Eastern Conference table with Toronto (17-7) their nearest rivals. Boston had led 29-28 after the first quarter but Chicago romped clear in the second, surging into a 56-42 lead at the half.

Chicago managed to keep Boston at arm’s length through the third quarter, maintaining a 15-point cushion at 78-63 heading into the fourth. Chicago kept up the pressure in the final quarter, outscoring Boston by eight points to close out a deserved win. “Sometimes, you get your butt kicked – it’s as simple as that,” Celtics coach Brad Stevens said.

“Chicago dictated the whole game, they played harder than we did, they played with more presence than we did, they played more competitive than we did, they played with more authority than we did. “You’re not going to win very many games when you play like that.”