Leeds eventually went in front through Austin, who scored with a powerful drive from just inside the box in what was the game's first shot on target.
The visitors almost found an equaliser through Harry Bunn, but he smashed a presentable shooting chance high and wide.
They were made to rue the missed chance as Antenucci followed up to score United's second after Giuseppe Bellusci's shot cannoned back off the crossbar.
Following the restart, there were shouts for handball from the Leeds fans as Mark Hudson charged down Antenucci's shot, but the referee was uninterested in their appeals.
Austin then played through Doukara, but Smithies was equal to the striker and made a smart save to deny him a goal.
Doukara was not to be denied a second time, however, and added a third for Leeds after stepping inside Hudson before slamming home.
Gaetano Berardi was shown a second yellow card for Leeds late on after another foul on Bunn, but it mattered little as the hosts closed out the game to secure all three points under Neil Redfearn's caretaker management.