Before Jayson Tatum left the Celtics' 119-95 blowout win over Memphis on Wednesday night with a groin injury, he was the best player on the floor. Two nights earlier, Tatum was once again in basketball-assassin mode in a 32-point drubbing of the Los Angeles Lakers. As Tatum went about burying one big shot after another in both games, pushing both Memphis and the Lakers into an abyss that they never could quite escape from, Kemba Walker wasn't too far away, smiling at the masterful work being put in by his teammate.