Skipper Jurgen Cavens put Lierse ahead after 11 minutes when he was set up in the box by Egyptian midfielder Sherif Al-Beyali.
The visitors restored parity on the quarter-hour mark, thanks to a Gregory Lino strike.
Two minutes later the in-form Abdul-Wahed notched his team's second, his 10th goal overall in the league this season, with a left-footed shot.
Cavens put the icing on the cake 19 minutes from time.
Egyptian trio Abdul-Wahed, Al-Beyali and Ahmed Samir were all named in Lierse's starting line-up.
Lierse, who have five league matches in hand, are now on 62 points in second place, three points behind leaders Sint Truidense.
By the end of the season, the league winners will be automatically promoted to the Belgian Jupiler League, while the next four teams in the table will face each other in play-offs.
The winners among the four teams will then take on the first-division penultimate outfit in a make-or-break game, and the victory will give either side a first-division spot.