Davis Cup captain Lleyton Hewitt is confident both Bernard Tomic and Nick Kyrgios will be fit to take on the USA in the Davis Cup on Friday.

Kygrios withdrew from his semifinal clash with Stan Wawrinka in Dubai last week with a back injury, while Tomic was hampered by a wrist injury during his run to the final in Acapulco.

But Hewitt said he expects both will play.

“Yeah I am (confident they'll play),” he said.

“Both Nick and Bernie are playing extremely well at the moment. The biggest thing for them is to get their bodies as close to 100 per cent physically (as they can). They've had the matches, they're confident, they feel good out on the court at the moment and they back themselves on the big points.

“That's why it's important for them now to more mentally prepare than anything. They've beaten quality players over the last couple of weeks.”

Tomic said his wrist has been causing him serious discomfort.

“I have a wrist problem,” Tomic said after his loss Austrian Dominic Thiem.

“Every match I played (in Mexico), I had a problem.

“It was very tough for me, I had to take pain killers so I hope it will feel better for Davis Cup. I have to play on Friday — how I will do that, I have no idea.

“It's very, very important for us, Davis Cup, and something special for me.

“But my wrist is bothering me a lot.”

Australia play the US at Kooyong from March 4-6.