The Cherry and Whites took command of Pool One when they dispatched the Exiles 29-22 at the Madejski Stadium last weekend and know victory over their Aviva Premiership rivals will improve their two-point advantage at the summit.
"It's a job that's only half done at the moment. It was great to come back the way we did last weekend against Irish, but they showed what a dangerous team they are and what they're capable of," Davies said.
"We really weren't at the races in the first half last weekend, which was a bit disappointing. We've been like that a couple of times this season and have to guard against that.
"But it's a great opportunity for us, we've got ourselves into a very strong position and we're really looking forward to Saturday's game."
Scrum-half Jimmy Cowan, openside Akapusi Qera, number eight Ben Morgan and centre Billy Twelvetrees are restored to the starting line-up.
Irish select Shane Geraghty at fly-half as they seek to regain the top spot they surrendered last Saturday.
Director of rugby Brian Smith believes the Exiles are a work in progress and is satisfied with their development.
"There is a lot of talent, but we have yet to become a hard-nosed winning team. We were aware of that when we inherited the squad, but we are developing nicely," he said.
"A lot of elements of our game are improving. We have made massive gains in the set-piece and in our driving game and in our scrummaging. We want to make sure we are a very difficult team to score against."