Big-serving Victorian Sam Groth has replaced Nick Kyrgios for Sunday’s Davis Cup singles clash against Kazakhstan in Darwin.

And Lleyton Hewitt is also on track to play on Sunday as Australia attempt to keep their title hopes alive.

Australia trail 2-1 in the tie after Kyrgios and Thanasi Kokkinakis lost their singles matches on Friday, before Groth and Hewitt combined to win Saturday’s doubles.

Groth will take on Kazakhstan’s top-ranked male, world No.63 Mikhail Kukushkin.

If he wins that to level the tie, Hewitt is expected to replace Kokkinakis for the deciding singles rubber.

Kyrgios courted plenty of controversy of his own during his run to the fourth round of Wimbledon, and the headlines have continued to flow since he arrived back in Australia.

The 20-year-old conceded he felt mentally drained during Friday’s shock loss to world No.115 Aleksandr Nedovyesov.

Masur said he understood why Kyrgios was struggling on the court after constantly dealing with the spotlight.

“That’s no different to being physically exhausted after a big month or a big match,” Masur said.

“It takes its toll.

“I kind of feel sorry for Nick in a way because it was almost a little bit of hysteria about some of the stuff that went on at Wimbledon.

“The press cycle just kind of went into overdrive,”