Videos: How has Boston been able to beat the 76ers?

How can a team down three of five starters possibly hope to compete in the postseason?

It's quite a reasonable question, but one the Boston Celtics have been forcing NBA analysts to consider in new ways after taking a two-to-zero series lead in the Eastern Conference Semifinals series against the Philadelphia 76ers.

You might point to the unexpectedly aggressive play by Al Horford, or the burst of growth we've seen in Terry Rozier and Jayson Tatum. One might add the tenacity and resilience of Marcus Smart and Jaylen Brown, battling back from lesser injuries to provide meaningful boosts on both ends of the floor.

You could probably come up with at least three or four other factors, boosts from guys who will sit for several games in a row, then get their number called and answer with outstanding contributions even after riding pine for days, if not weeks. With so many key players hurt, nobody stays seated for long.

There's a fair amount of strategy involved too, though - Brad Stevens' wizardry with the Xs and Os has been as much of a factor in this unexpected run as anyone's on-court contributions have - so, watch the videos below to hear what the word on the street is regarding what is driving this Celtics team's success.

For more stories by Justin, click here.

Image: Jesse D. Garrabrandt/NBAE
Video: TNT/ESPN/USA Today
Follow Justin at @justinquinnn