Cape Town, Oct. 27 -- Australia have suffered a major setback ahead of the third and final Test against South Africa, with Steve Smith ruled out of the series decider due to a neck injury.

Smith experienced neck stiffness during Australia's match-eve training session and was scheduled to undergo a fitness test ahead of the crucial encounter. However, the experienced batter was left out of the playing XI for the final Test at Newlands in Cape Town.

The injury concern had also troubled Smith during the second Test in Gqeberha, where he was unable to bat for an extended period as Australia slumped to an innings-and-31-run defeat.

Australia have made four changes to their playing XI for the series decider, bringing in Josh Inglis, Cameron ...