Though they're together now, there was a time when Miami Heat head coach Erik Spoelstra shared a rivalry with Jimmy Butler and the Chicago Bulls.

Spoelstra says he and Butler discuss their former rivalry from time to time, hearkening back to the 2013 Eastern Conference Semifinals. It was a time in which LeBron James was still a member of the Heat, and Butler was a rising star with the Bulls. The play was tough in that series, with several technical fouls and ejections along the way, including those to Taj Gibson and Joakim Noah.

In the end, the Heat went on to defeat the Bulls en route to an NBA title:

“He always makes it a point about how the Bulls didn’t like us,” Spoelstra said, via K.C. Johnson of NBC Sports Chicago. “One of our first conversations, I was like, ‘You underestimated how much we disliked you as a team.’

“I’m dead serious,” Spoelstra added. “We didn’t like them. They didn’t like us. That’s what you want in a playoff series, borne out of respect and high-level competition with type-A personalities going after each other.”

Butler joined the Heat this summer by way of a four-team trade. So far, he's proving to be a fine acquisition, but it sounds like he hasn't forgot about his days of facing Spoelstra.

In his 10 appearances with the Heat this season, Butler has racked up averages of 18.7 points on 42.0 percent shooting from the field (27.6 percent from beyond the arc), a career-high 7.0 assists, 5.7 rebounds and a career-high 2.7 steals in 34.3 minutes per outing.

The Heat improved to 10-3 with Wednesday night's 124-100 victory over the Cavaliers. Miami will be back in action on Friday night, as they're scheduled to face the Bulls. Tip-off inside the United Center is set for 8:00 p.m. ET.