Complex sentence: Rick Carlisle has been the head coach of the Mavericks since 2008, and led the team to their first championship in franchise history in 2011, against their same 2006 Finals opponent, the Miami Heat in a rematch.
Split into simpler sentences: Rick Carlisle has been the head coach of the Mavericks since 2008. Carlisle led the team to their first championship in franchise history in 2011, against their 2006 Finals opponent, the Miami Heat, in a rematch.