I have to ask--why did you keep taking a side-facing stance when he took your grip?
I was moving in for uchi breaks. Works like a charm on damn near everyone for me. Obviously he has the skills to shoot holes in the strategy. However, no matter what I do I am outgunned.I was trying to be aggressive rather than defensive. I knew it was going to open me up, but its cool, that is what practice is for.
I only have about 4 years of Judo training, and I'm not very good at randori, but it just looks like you are asking to be swept with your foot like that (and he obviously obliged). Being aggressive probably is your only option against someone of his skill level, but then the point is to learn, not to win, so as long as you learned in the process then it was a successful randori session :)
My uchi attacks are usually pretty solid for up to about a 3rd or 4th dan player. What makes it look like I am ineffectively just sticking my leg out is the fact Matl Sensei is responding correctly, negating my attack and putting me in a bad position with simple tai sabaki. Makes me look and feel ineffective. But the thing to watch is not my ineffectiveness, it is what response he countered an attack to make it appear totally ineffective.