Lleyton Hewitt is under no illusions.

Australia’s captain says it will be tough going in the Davis Cup tie against an unheralded Bosnia and Herzegovina starting on Friday.

Hewitt’s Australians take on the Bosnians at Adelaide’s Memorial Drive with Alex de Minaur and John Millman in singles action.

Millman opens the tie against Bosnia’s top-ranked Damir Dzumhur in the opening match with de Minaur meeting Mirza Basic.

On paper, the Australians are heavy favourites: Millman, world No.36, against Dzumhur, world No.52; and de Minaur, world No.28, against Basic, world No.99.

But Hewitt says the Australians have every reason to be wary of their opponents.

“We know how tough this match is going to be,” Hewitt said.

“Their players play extremely well on hard court.

“All we can do is control what is in front of us and our preparation has been fantastic.

“I’m so proud of these boys and how they have come straight off of a big Australian summer but still had this down as a massive priority for them.

“Not everything is going to go perfectly over the next two days but we have to try and fight through that and find three out of the five wins that we need.

“We certainly respect these guys that we’re playing against.”

Hewitt has paired John Peers and Jordan Thompson for Saturday’s doubles match against Tomislav Brkic and Basic, to be played before reverse singles matches.

There is no room for error in the revamped Davis Cup format: lose the tie, and the Australians won’t contest the finals in Madrid this November. Win, and they’ll join 17 other nations in the finals.

“We haven’t even thought about the finals and possibilities of that,” Hewitt said.

“We’re trying to cross this bridge now and we know it’s going to be a tough match this weekend.”