One-on-one from both ends, check the ball to start play. Defenders must stay between the dribbler and the basket, contest the shot, box out, and rebound. Turn and sprint to a new spot if beaten, but not too close to the attacker, or he will crossover and beat you again. If slower than the attacker, play off him. Don't "ride" the attacker (run shoulder to shoulder), you will foul or he will beat you. Instead, separate from him, pick a spot and sprint to get ahead. Switch at the other end, then go against players that are faster and slower.
Here X1 is quick enough to stay with 1, whereas X2 is slower than 2 and drops off to keep a cushion.
See Defending - DeMatha zig-zag, 1 on 1 - Zig-zag to transition, 1 on 1 - Hot knife through butter, Pressing - White and black, Billy Tubbs, Pasquali.