Captain Dalton Papali'i said Cotter had brought another edge out of the side.
"He's come in and is getting the best out of everyone. He's told us forwards that we're a good pack, and if we can roll our sleeves up and get into our work, it'll be hard to stop us.
"We've shown glimpses of that. Last week was a bit of a hiccup but we came out on top with good things. He's brought that edge and he gets the best ouf of players. He's good in relationships with individuals and we want to play harder for him."
A feature of the side named for the game is the return of loose forward Cameron Suafoa, who has completed radiation treatment for a cancerous tumour on his back.
Assistant coach Craig McGrath said Suafoa's attitude was such that if you didn't know he had been receiving radiation treatment for a tumour on his back, you wouldn't know.
"It was three, four weeks into his treatment that he came to Vern and asked to have a couple of weeks off because he started feeling tired. He doesn't make a fuss of things. He's just got stuck in and carried on with his work.
"He even played some games when he was getting treatment."
Suafoa then told Cotter that he wanted to go on the trip.
Captain Dalton Papali'i said Suafoa had shown a lot of resilience and courage in doing what he had. He had come back into the side because he had itchy feet during his treatment.
It was inspiring, and Papali'i said there was often talk about tough players in sports who made big hits and big runs and were into contact, but what Suafoa had shown was 'true courage and real toughness. '
"To go through all that treatment and still be showing up day in, day out training with us and putting his best foot forward, I don't think I could do that. I'd be struggling.
"But he showed no weakness, he just carried on with that. I look up to that, and I'm close with him, so it was pretty special to see how he's come through it and he's not missing a beat. It's like he never left."
Against the Rebels, tighthead prop PJ Sheck, who has played for Wellington in the Bunnings Cup, will debut after joining the side from the Highlanders this year.
McGrath said Sheck had taken time to reach the standard the Blues wanted, but he had worked hard and deserved his opportunity.
"I've been impressed with him getting his head down, keeping it down and working hard. He's worked really well."
Halfback Taufa Funaki and first five-eighths Harry Plummer will be paired again, and McGrath said they had played a lot together at NPC level and it was great to see them going well at Super level.
"They're doing a good job driving our team around the park. Taufa has been super impressive. He's quick to rucks, physically around his defence, and physically with the ball carrier. He suits the game Vern wants us to play, where nines [halfbacks] get out, poke, and put other people into space.
"Harry's making every place the winner. He's done some good things, particularly last week, he drove our team and got us back into the late win. It's now on Finn [Finlay Christie] and Steve [Perofeta] to work their way back into the team."
