كتب : Sherif Tarek
Skipper Jurgen Cavens put Lierse ahead only after two minutes, but the visitors leveled shortly on four minutes.
Julien Tshiala restored the hosts' slender lead again four minutes from the half-time, but Waasland got back on level terms again 15 minutes after the hour mark.
But Stefan Nikolic hit a last-gasp screamer for Lierse deep into injury time to allow his team to go through.
The first leg ended in a 1-1 draw, which makes the aggregate result 4-3 for Lierse.
Egyptian midfielder Mohamed Abdul-Wahed was included in the starting eleven, and was substituted on 70 minutes.