) Australia captain Pat Cummins declared the host's first innings at 475-4 during the lunch break on the fourth day of the third Test at a rain-affected Sydney Cricket Ground that has lost four straight sessions to the weather.

After no play on Friday, further rain on Saturday meant that players were unable to take the field up to lunch, effectively forcing Cummins' hand into declaring to give his bowling attack any hope of prising out the 20 South Africa wickets it needs to take victory in only five remaining sessions of play.

The declaration leaves Usman Khawaja stranded on 195 not out, tantalizingly close to his maiden double century.

The forecast appears more favorable for the remainder of the Test.

"Time is the enemy," Khawaja said after Friday's washout.

"A result is unlikely, let's be honest, but it's still possible." Australia has already won the series after two crushing defeats in the first two Tests at Brisbane and Melbourne.

A win for Australia in this third test would confirm its place in the World Test Championship final to be played at Lord's in England in June this year.

Earlier in the match, Khawaja scored his third straight SCG ton and passed his previous highest test score of 174 — against New Zealand at Brisbane in 2015 — and shared a 209-run partnership with Steve Smith (104) to lift Australia to 475-4 when rain stopped play on Thursday's second day. Wet weather wrecked the chance of any play on Friday.

Matt Renshaw, in his first Test since 2018 playing for the injured Cameron Green, returned a positive test for COVID-19 just before the match began and was separated from the remainder of his teammates and moved to another change room at the SCG.

Australia team management confirmed that Renshaw has since returned multiple negative tests and has been cleared to rejoin the side. He batted at No. 6 and was five not out at the declaration.