The New Zealand-born Wales international hailed the quality of the Swansea-based side and believes the Blues will have to work hard to come out on top.
He said: “They have a monstrous pack, probably one of the biggest in the competition. They know what their game is about and we have a massive challenge to compete with them.
“We know how tough it will be, we have been buoyed by a couple of tough losses in recent weeks.
“Ospreys have some world-class players right across their team with some putting their hands up for the Lions.
“We have a huge challenge against them, they put us to the sword last time and we need the right attitude to get stuck in.”
Anscombe scored 17 points in last season’s 40-27 Judgement Day loss to Ospreys.
And Steve Tandy’s side thumped the Blues 46-24 at the Liberty Stadium in October in the Pro12, a result that disappointed former Chiefs star Anscombe.
“We came back from Ospreys last time with our tails between our legs,” he admitted.
“We physically did not front up. It is key in derbies to be physical otherwise it is a tough day at the office.
“I think our performances are heading in the right direction. But the Ospreys are a top, top team. They will present us a challenge.”
The 25-year-old heaped praise on the Judgement Day concept and reckons the atmosphere makes it a fun family day out.
“The last two occasions I have played at Judgement Day they have been awesome and a great idea by the WRU,” said Anscombe.
“In terms of crowd numbers it has been fantastic, it does not take much to get up for it.”
