England captain Alastair Cook was unbeaten on 7 with nightwatchman James Anderson 1 not out at the end of play.
Smith's second century in three tests came off 142 balls and included 16 boundaries and a six over mid-wicket off Borthwick to move to 99, followed by a four in the same over to reach the milestone to the delight of a boisterous SCG crowd.
For the third time this series, Haddin played a key role in rescuing Australia's innings, scoring his sixth half century of the Australian summer as part of the 128-run stand with Smith to put the hosts in good position to achieve a 5-0 series sweep over England.
However, with his second century of the series beckoning, Haddin mistimed a drive and edged to Cook at first slip for Stokes' third wicket of the innings.
