They are 10th on the table, two points behind the Crusaders, but perhaps crucially, with a game in hand over the seven-time champions.
With Jerome Kaino, Charles Piutau and Dan Bowden out injured and prop Charlie Faumuina rested, the Rebels will test the Blues in all areas.
One player who could turn the match is Blues midfielder George Moala, a man likely to have a new lease of life after his discharge without conviction on an assault charge which has been hanging over him all year.
"They're a very good side," agreed Kirwan. "They're well drilled with good leadership and hold the ball for long periods. We're going to have to be patient, we're going to have to break them down. Guys like George are going to be important to get us over the advantage line."
"If you don't bend them and get over the advantage line their defence is very, very good so we're going to have to vary the way we play and keep throwing things at them."
One of the Rebels' key figures is loose forward and co-captain Scott Higginbotham, who equalled former Wallaby Owen Finegan's record for the most tries as a forward when he crossed for his 29th career touchdown against the Chiefs.
Kaino's absence with a dislocated finger could be felt here, but Kirwan will be confident he has the loose forwards to stop Higginbotham in new skipper Steven Luatua, Brendon O'Connor and 19-year-old sensation Akira Ioane.
"We have key people we talk about each week in our defensive system and he [Higginbotham] is one of them for sure," said Kirwan. "He's a pretty inspirational leader and he runs hard and offloads. He's having a really solid season and if people like him have a good season the team follows."
Bowden's groin injury has opened the door for Ihaia West to start.
After tonight's match the Blues play their final four games of the season against the Bulls, Hurricanes, Crusaders and Highlanders at Eden Park in Auckland.