Blues coach Tana Umaga is confident ahead of his side's clash with the lowly Cheetahs but refuses to underestimate the South African side.

The Cheetahs are already well out of the running for a Super Rugby finals berth but Blues boss Tana Umaga says his troops are braced for a genuine battle at Eden Park.

The Bloemfontein-based side have won just two games this campaign and threw away a 41-24 lead against the Highlanders last week, shipping three tries in the last five minutes to lose 45-41.

The Blues, meanwhile, look high on confidence after their wins against the Brumbies and Waratahs and are heavy favourites for Friday's encounter.

Nevertheless, Umaga predicted a Cheetahs outfit "desperate" to prove their worth on the Super Rugby stage.

He said the Cheetahs were possibly the club's hardest African opponents with their penchant for running rugby, and would be written off at his side's peril.

"They'll be disappointed coming off that (Highlanders) performance for them at home, so we'll probably get the backlash of that," Umaga said.

"(But) we're at home ourselves and we want to keep moving forward with what we want to achieve."

Umaga also underlined the importance of winning all five of the Blues' remaining Super Rugby games, to give themselves a sniff of the finals.

That task has been made considerably more difficult by the loss of Sonny Bill Williams, who is nursing a concussion, as well as the continued absence of co-captain and enforcer Jerome Kaino.

Akira Ioane has stepped into the All Blacks stalwart's shoes during his recovery from a torn meniscus and impressed Umaga with his precocious talent.

"He's doing very well for his age group - he's still got a bit of improvement to do, but we're very happy with him, he's stepped up to the job at hand," Umaga said.

"He's pretty good now, so imagine what he's going to be like in two or three years' time, when he really gets the hang of the role."