Du Plessis batted for seven hours .
Du Plessis faced 376 balls , sprinkling 14 boundaries into a gritty defensive knock to ensure back - to - back draws between Australia and South Africa in a series for the first time since 1921 .
Du Plessis batted for seven hours and faced 376 balls , sprinkling 14 boundaries into a gritty defensive knock to ensure back - to - back draws between Australia and South Africa in a series for the first time since 1921 .