A brace from on-loan Norwich midfielder Luke Chadwick eventually earned the visitors the spoils despite Tamika Mkandawire’s late consolation for Orient, who also missed a penalty when Adam Boyd crashed wide following Shaun Cummings’ 50th-minute foul on Sean Thornton – which also earned him a red card.
Dons went close to a sixth-minute lead when Jude Stirling side-footed against a post, but they broke the deadlock inside 20 minutes when Chadwick exchanged passes with Peter Leven and easily beat home goalkeeper Glenn Morris.
Chadwick then added the final touch to a cross from midfielder Mark Wright to grab his second after 23 minutes after being left unmarked.
Orient wasted the chance to reduce the arrears when Boyd fired his penalty wide after Cummings had earned a red card for up-ending substitute Thornton.
There was time for Mkandawire to lash home a consolation goal, but it proved in vain for Martin Ling’s side.