He said, "They're the top team. They'll be comfortable with us coming down. They dominated us only a month ago, so they'll be thinking it's an easy game for them.
"We'll do down there and try and challenge that mindset and put in a decent performance."
Cotter said the Blues needed to clarify what they were trying to achieve and be more effective at implementing it.
"It's not as if we're playing badly all the time. We're not finishing our second halves."
Cotter said the news around Beauden Barrett's broken hand was more positive than previously thought, and he could be back in action in three or four weeks. The options he gave the side were demonstrated in the first half against the Brumbies, and the profile of the side was changed.
It was timely that Stephen Perofeta was available and would start from the bench. He can see space.
"He's got a very good rugby brain, so wherever you put him [first five-eighths or fullback], he nuts it out. He's a smart guy and a good communicator, we're glad to have him back."
Captain and lock Patrick Tuipulotu said while they were scoring good tries early in games, they had failed to keep scoring points, especially in the second halves.
They were also working hard at tidying their lineouts where they have come under pressure from opponents competing for the ball and attacking the Blues' lineout maul.
"Last year we thrived in that area and that's where, this year, a lot of teams are putting us under pressure."
Chiefs coach Clayton McMillan has welcomed back All Blacks' first five-eighths Damian McKenzie, whose knee injury proved to be bone bruising that saw him recover quicker than earlier feared. He will start on Saturday along with captain and No8 Luke Jacobson.
"It's good timing because Josh Jacomb has had four big games in a row, with big minutes, so it is an opportune time to bring him off the bench."
McMillan expects to see the best of the Blues on Saturday despite their recent record and their first-round loss to the Chiefs.
"No game against the Blues is ever easy and the games they've lost have all been by small margins and could have easily gone the other way, even the game that we played in round one. So we are taking nothing for granted."
He said other teams have adapted to what made the Blues so successful last year, and the Blues have also evolved and are creating opportunities a little wider where they have 'magnificent firepower'.
Keeping them in the right positions on the field and denying them the chance to play to their strengths is essential, while getting territory and accumulating points is vital.
"If you make errors in your half, it's generally going to be exposed and you open the door to the opposition to put points on you, then you can be chasing the game pretty quickly."
Shaun Stevenson is back at fullback, having completed a stint in Japan where he enjoyed playing a different style of rugby.
He feels energised, mentally refreshed, and keen to play with the changed laws that he thinks have helped the game.
"The boys have been going well since I've been away, so I'm not looking to reinvent the wheel. I'm just coming in, doing my job, and hopefully helping them score a few tries in front of our home fans.
"The Blues are a classy team that haven't had the results go their way. They'll be hungry. They'll bounce back and we've hopefully come up with a good game plan this week to nullify that."