Wallabies halfback Will Genia has been taken for scans on his injured knee and could be ruled out of the squad that will travel to Argentina for the second Test of the Rugby Championship.

Genia played only the first half of Australia’s dramatic 24-20 comeback win over South Africa on Friday night in Brisbane, having limped off at the break with suspected medial ligament damage.

Winger Rob Horne is also in doubt after straining his calf, with coach Michael Cheika keen for a proper assessment on the pair before settling upon the make-up of the squad that will travel to South America on Monday.

“It doesn’t look too bad according to the physios at the triage part now,” Cheika said of Genia.

“He’ll go off for a scan now, as has Rob Horne with a little bit of a calf, so we can get some assessment on them before we decide who’s travelling to Argentina.”

Cheika is expected to err on the side of caution with Genia and leave him behind in Australia if there is any risk.

Nick Phipps came on for Genia in the second half and could yet have the chance to make up some ground in the race to become Australia’s first-choice No.9 at the World Cup.

Veteran Matt Giteau also came away from the Springboks clash worse for wear, copping a hit to the nose that forced him off the field for a stretch in the second half with blood gushing from his face.

In his first Test match in four years, Giteau looked on-song but it was a rocky night overall for the Wallabies’ much talked about 9-10-12 axis with Genia and Quade Cooper.

Cooper’s stocks may have fallen to a degree following an unconvincing performance at five-eighth, and the Wallabies looked a more potent outfit when he was swapped with Matt Toomua for the last 10 minutes.

The 27-year-old had an indifferent night and failed to provide the polish that many were hoping he would bring to Australia’s attack.

But he remains in Cheika’s good books, even accounting for his daring behind-the-back flick pass that so easily could have resulted in a Springboks try deep into first-half red time.

“Fine,” Cheika said when asked how the coaching box reacted to it.

“If Tevita (Kuridrani) takes that ball, he’s away … we score at the other end of the field at half-time.

“I’ve got no issue with that one at all,

“I’m never going to tell a player not to do that … because he can do it and made the pass. I’ve seen him do it at training so there’s no reason why he can’t.

“(Kuridrani) was probably shocked it came out because it was an incredible ball.”