I've been thinking about those defenses and counters a lot lately, with the current Sherkmania that has taken over some of the MMA Forums on the Internets these days.
I was rewatching the Diaz/Sherk fight. Nick showed some excellent single leg defense in that fight. Including this move ...
One mistake Nick makes is trying to go for the switch while Sean's head is on the inside. From what I remember, you've got to move the head to the outside--otherwise the guy's head will be in the way.
With the head inside, Rodrigo had us push the head down, turn inside and put the held knee to the mat, then kick forward with that leg, goose-stepping your way out of the single-leg. You can see how that would have worked for Diaz here.
