Why is it that teams with good defensive reputations seem to lose that "pendulum" player patrolling the baseline with such regularity? In the Sweet 16 game against Mississippi State last year, the Bulldogs (supposedly a very good defensive team) constantly were surprised by passes into Morgan Tuck, who was behind all of their defenders under the basket. (They were playing man-to-man, which makes it even more surprising that she got lost.) And nearly every game this year, I see Gabby or Napheesa (or sometimes even Natalie -- how can anyone lose her?) take a pass for a layup after the baseline defender has gone to help (presumably) on wherever the ball was.
It's as if they think they are playing soccer, and that an offside flag will go up if a pass is made to a player who is behind the last defensive line.
In man to man, I think it is usually just the result of constant motion and screening and defenders getting mixed up on who has who where.
In zone it is the result of making specific zone players commit to another player in their area of responsibility, and the other zone players not rotating to cover - fast passing causes lots of stresses on a zone.
One of Uconn's great defensive strengths is their rotation to cover as the ball moves, as well as their rotation to cover in man when a help defender leaves their man. It is still a little ragged this early in the year, but even now it is light years ahead of a lot of teams. How often have we seen a guard who has left their man out top pick off a pass to a player heading to the basket after their defender has gone to help on someone who drove. Moriah seemed to get about one a game, and Kia, Chong, and Dangerfield are trying to duplicate it.
When you watch Geno coaching the details of defense - the shading of defense stance to force players one way or another into help, the rotation of defense off the ball, the minutia of being a good defensive team, it is really fascinating. And then watching many other teams playing who just don't have a clue. CViv games used to drive me nuts, but she was a great teacher of defense and her good teams played really smart tough defense. Not sure some other coaches spend ten minutes teaching defense in practice.