7 NBA teams which could upset the Golden State Warriors/Cleveland Cavaliers

#4 Boston Celtics

Coach Brad Stevens is undoubtedly one of the best in the business

The Celtics have emerged as a scrappy team with tenacious defense. They are not an opponent to be taken lightly on any given night, as they want to beat you with their defense.

In the off-season, they've added Al Horford to their roster, which gives them a strong interior presence. In the past, they just had Isaiah Thomas to rely upon to generate offense in a pinch. Although a capable all-star, teams were able to collapse on him and put the muzzles on the Celtics offense as a result. Horford will make teams pay for pursuing that tactic with the resultant space he gets to play with.

And if the rumors of Blake Griffin or Russell Westbrook going to the Celtics are true, consider this team as a lock for the conference finals, and perhaps beyond