Bournemouth had gone in front through Ryan Fraser’s clinical finish three minutes before half time.
But Austin found the net just after the hour mark and celebrated in front of the Cherries fans.
Austin could have won it for the visitors but headed a Ryan Bertrand cross over the bar.
And Callum Wilson should have done better with a bitched rebound attempt off Josh King’s shot at the other end.
The draw sees Southampton move above Brighton in 11th place, while Bournemouth climb two spots into 14th.
Full report to follow…