AA Gent missed striker Laurent Depoitre and midfielder Daniel Milicevic, but their substitutes, forward Khalifa Coulibaly and winger Benito Raman, played an excellent match. Both had one goal, as AA Gent had plenty of goal-scoring opportunities.
Westerlo lost midfielder Jore Trompet with two yellows before the break and escaped worse in the second half. Captain Sven Kums converted a penalty and scored from a free kick to make it 5-0.
AA Gent travel to France for the crucial Champions League tie at Olympique Lyon on Tuesday. They will have to play without their fans though, a measure taken by the French authorities in the aftermath of the Paris attacks. If Gent don't lose, they are almost certain of 3rd place in the group and an Europa League berth in spring.
A minute's silence was respected before kick-off to honour the victims of the Paris attacks. Extra safety measures applied to the match, with fans being body-searched.