Grayson Allen has not made more than three shots from the field in a game since Feb. 9. Key three: Duke men's basketball vs. Clemson Duke will open ACC tournament play needing a win just to get into the quarterfinals for the second straight year, as it prepares to face No. 12 seed Clemson. The Blue Devils are playing for a potential top-four seed and a trip to Greenville to start the NCAA tournament. Here are three keys to the game:Slow Down BlossomgameClemson’s entire offense flows through its best player, redshirt senior Jaron Blossomgame. The third-team All-ACC selection is a matchup nightmare for opponents at 6-foot-7, as he can punish smaller defenders in the post and has the quickness and shooting touch to step out to the perimeter to exploit big men who try to guard him. He is averaging 17.5 points per game and is a strong finisher at the rim who likes to crash the offensive boards to secure second-chance buckets. Duke senior Matt Jones will likely draw the task of slowing Blossomgame, which he did effectively in the regular season, but it will require an entire team effort to stop the redshirt senior, who will attempt to exploit Duke’s lack of size inside. Protect the InteriorThe last time these two teams matched up, the Blue Devils came away with a hard fought 64-62 victory. But Duke was shredded inside, as the Tigers held a 34-18 advantage in the paint. Sophomore Elijah Thomas was the main culprit, notching 15 points and nine rebounds and exploiting graduate student Amile Jefferson in the point. Rebounding has been a problem for the Blue Devils all season, and Duke was pounded inside once again in their last game against North Carolina. Figuring out how to protect the defensive glass will be critical for the Blue Devils against Clemson and as they continue in the ACC tournament if they win.Get Grayson Back on TrackJunior Grayson Allen has been cold lately, only shooting better than 40 percent from the field in one of Duke’s last six games. Allen has also been nursing an ankle injury that forced him to miss the Blue Devils’ loss to Miami and has seen him come off the bench in the past two games. The mercurial shooting guard has seen his share of controversy this season, but is key to Duke’s chances of winning its 20th ACC championship. The Jacksonville native rediscovering his shooting stroke would give the Blue Devils another reliable scoring option on the perimeter and take pressure off of sophomore Luke Kennard, who has had to carry an increasing amount of the offensive burden.