Jenkins played a crucial role throughout the RaboDirect PRO12 encounter by winning several penalties in the set piece and loose.
But Attack Coach John admitted Jenkins impact was just as big off the field with his attitude and high standards rubbing off on his team-mates.
John said: "Gethin has been phenomenal since coming back from international duty. He hasn't even had a break, we offered him a week off after the international series and he didn't want it.
"He has been captain, as Smiler (Matthew Rees) wasn't quite back, and he has been superb.
"He plays like a back row forward at the breakdown. He has played and trained with a smile on his face for the last four to five weeks and you can see that is paying dividends.
"What he does in training is demand high standards of other people. He is not afraid to tell people if they are doing the wrong thing or in the wrong place.
"You need that and you need to be accountable. When it comes from within, as well as me and Chief (Dale McIntosh) barking at them, then it can be more powerful.
"Smiler, Bradley (Davies), Lou (Reed) when he is back playing and Gethin have been an example to them all and the boys are following them."