Cassisi, 26, said he rated the Bulldogs as highly as the Saints and Cats, and identified their forward line and midfield as particularly strong.
"Their form of late has been very good, they've won a few in a row and they've pushed Geelong as good as anyone this year," he said shortly after the Power touched down in Darwin on Friday.
"All indications show the Bulldogs, Geelong and St Kilda are really pushing hard at the top of the ladder, but in saying that we're only one loss behind them.
"They've got a very even team and their forward line is obviously very dangerous with Brad Johnson playing up there, and Josh Hill.
"They rotate a lot of their midfielders through there as well so it's just going to be a big night of communication between our midfield and our backs, just to make sure we're on them and close checked."
Cassisi agreed with Bulldogs' captain Brad Johnson on the importance of Saturday night's four points and said the Power must attempt to find consistency now with only 10 games remaining in the home-and-away calendar.
"This is our opportunity to play a team in the top four and really see where we're at," Cassisi said.
The Power have won six games for the season but only two in a row back in rounds three and four.
Cassisi said there was no definite explanation as to why his side has had such a topsy-turvy first half of the year.
"It's hard to put our fingers on one particular thing but that's what we're working really hard on, trying to build some consistency in our season," he said.
"Winning last weekend provides us with an opportunity this week to string two together.
"You go into the halfway mark with seven wins and five losses and a refreshing look at the second half of the season to set up a finals berth."
He also backed the form of his side and the ability of this week's inclusions Daniel Motlop, Robbie Gray and former Tiger Danny Meyer.
"The side's looking really good. We've got a few injuries at the moment but the guys that are coming in have all been playing really well in the SANFL so they come in with form," he said.
Motlop said he was pleased to be back in the side after missing the past fortnight with an ankle injury.
"It's good to come back after a few weeks off, and I'm fresh now and ready to go," he said.
"The ankle feels good. I had a couple of weeks off to rest it and we've got another week off next week, so I'll play this one and then freshen up again for Geelong."
He also stressed how much the opportunity to play at TIO Stadium in his home town meant to him, and the Power's other Territorians Marlon Motlop, Peter Burgoyne and Tom Logan.
"We always hope we're playing in Darwin every year. The other boys are good about it too; they love playing up here too," he said.
"We're pretty excited. All our families are up here so we're just ready to go now and hopefully put on a good performance."
