The reigning champions were dethroned at the summit last weekend by Ospreys when they lost 29-15 to Edinburgh which ended their 14-game unbeaten run, but Holland is confident of putting that right.
The Welsh side meanwhile have been in imperious form, winning all five league games so far this term, Connacht the latest victims last Friday, 26-21 so the Irishman is under no illusions over the scale of the task.
He said: "It's our biggest game without a shadow of a doubt. We've had six games in the first phase and we targeted to win all six, obviously that hasn't happened, but without anyone saying it this was always going to be our toughest game.
"They are unbeaten and playing good football. They're a good side and we met them plenty of times last year, they put us out of the Heineken Cup last year.
"If we do perform to the best of our ability, like we've done in patches against Glasgow, Cardiff and Dragons, I have no doubt about it we are good enough to win.
"But we need a bigger effort, not just 10 or 15 minutes, we need an 80 minute performance. These 10 or 15 minutes where we get a couple of tries isn't going to be enough this weekend."
Three points separate the sides going into Saturday's game and Holland is adamant there needs to be an improvement in performance from the Edinburgh clash after such a slow start to the game.
"We were 16 points down after about 20 minutes and we were chasing it from then on. We didn't play our game, we didn't get into any flow in attack, the defence wasn't up to scratch," said Holland.
"It was just one of those matches where things didn't go right. It wasn't from a lack of effort we just weren't smart enough in those areas."
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