Thornton and McQuaid throw down in a heavyweight bout.

Boston Bruins' fans were in for a treat on Monday, as one of their former enforcers took on one of their current heavyweights.

During the second period of Monday's matchup between the Boston Bruins and Florida Panthers, McQuaid was called for boarding on Logan Shaw, and Thornton stepped in to defend his teammate.

Thornton, who spent seven seasons with the Bruins before joining the Panthers in 2014, was given five minutes for fighting, two for instigating and a 10-minute misconduct for his role in the scrap.

Here is the fight:

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Images Courtesy of Keystone Press