Strength With Grippers Going To Failure

[Rampage jackson]

Hi i have a question when im closing my no.1 gripper i can do max 11 full reps the 11 rep is full but Almost to failure

but the problem is that i do 3 sets so in the next sets i can't do 11 reps i get tired so i do 2-5 reps but if i do on the first set 6 reps so in the next sets i do 6 reps on all sets what be better ??