Benavidez did 2 very impressive guillotines at BW, against 2 legit BJJ black belts:
Miguel Torres- had him hurt already, slapped it on hard, got the tap.
Waggney Fabiano- went for guillotine during a scramble, gave up position to apply it, but Fabiano escaped using perfect technique. Benavidez slapped another one on a few seconds later, this time Fabiano was unable to escape quickly enough, and tapped. I think the first attempt might have almost finished Fabiano and he was still getting his bearings back when Joe B did the 2nd attempt.