The visitors travel to the Globe Arena as one of the few teams still to suffer a league defeat this season.
Four victories and seven draws see them sitting third in League Two, three points ahead of the 10th-placed Shrimps.
“They are doing very well and fair play to them,” Bentley said.
“They haven’t won the games they wanted to but they find themselves in the top three by being hard to beat.
“It’s a fantastic achievement and my hat goes off to them.”
Bentley’s Cumbrian counterpart Keith Curle is someone the Shrimps boss knows well from his time as a younger player at Manchester City.
As boot boy for Curle and other senior players at Maine Road, Bentley saw what it required to play the top level.
“Curley was one of the pros I looked up to, playing in my position,” he said.
“He was the captain and a big-money signing from Wimbledon for £2.5m.
“He was a fantastic pro, a great player and he always had a lot of time for the younger players.
“He’s doing very well in his managerial role.”
Two other familiar faces to home fans will be Carlisle’s Jamie Devitt and Sahun Miller.
Both rejected new deals with the Shrimps last season and moved to Brunton Park over the summer.
Miller’s one season with the club yielded 16 goals, while Devitt chipped in with another seven.
While acknowledging their abilities, Bentley told his players that Carlisle possess threats elsewhere.
“Devitt and Miller were two of our key players last year but they can’t get in their team,” he said.
“Nicky Adams was one of the best players I saw last season but they have got good defenders and attackers.
“Jabo Ibehre keeps chipping in while Charlie Wyke, the lad up front, is very good.
“They have quality all over the pitch and we know it will be a good XI and a squad looking to stay unbeaten.
“For us, we’ve won at home on Tuesday and we want to build on that with another win.
“We want to be the first team to beat them and that’s the carrot dangled in front of my players.”
Tuesday saw the Shrimps record their first victory in the Checkatrade Trophy with victory against Stoke City.
As Bentley admitted afterwards, it was a win which came at a high price with injuries to Dean Winnard, Ryan Edwards, Alex Kenyon and Aaron Wildig.
“I always say it’s a squad game,” he said.
“When anything does come along it’s a negative in that you lose a key player but it opens the door for someone to grasp their opportunity.
“We always talk about our subs coming on and affecting the game – last season our subs scored more than anyone else in the country.”