Anderlecht held in title playoff first leg
Jonathan Legear had put Anderlecht ahead in the 51st minute when he latched on to Olivier Deschacht's through ball but Liege equalised nine minutes later through Dieumerci Mbokani.
The two teams finished the season level on 77 points last weekend to force a playoff as the title cannot be won on goal difference. Sunday's second leg takes place in Liege.
Liege dethroned Brussels-based Anderlecht last term to claim their first Belgian first division crown in 25 years.
Both clubs have clinched a place in next season's Champions League qualifying rounds while third-placed Club Bruges and Ghent, who came fourth, will play in the Europa League.