Zulte-Waregem needed a 90th-minute winner from Jonathan Delapace to overcome the Belgian First Division’s bottom club Cercle Brugge.
Michael Uchebo opened the scoring for Cercle in the 33rd minute but the visitors were level two minutes before half-time after Mbaye Leye finished off Olafur Skulason’s fine pass.
Zulte-Waregem ruined the home fans’ hopes of picking up a crucial point when Delapace scored late on.
Saturday’s result puts second-placed Zulte-Waregem five points behind leaders Anderlecht, who have a game in hand against Standard Liege on Sunday.
Cercle are six points from safety after 14th-placed Lierse drew 1-1 against Lokeren.
At the Stade Charles Tondreau, Mons had to wait until the final quarter of an hour to wrap up their 3-0 victory over Waasland-Beveren.
French defender Gregory Lorenzi made it 1-0 from the spot in the 36th minute but the home side failed to double their lead until 12 minutes from time when Thomas Chatelle scored after being set up by Peter Franquart.
Arnor Agneli completed the three-goal triumph in the 89th minute as Mons drew level with Mechelen on 25 points in the middle of the standings.
In other results, Gent defeated Beerschot 2-1, OH Leuven held on for a 1-0 victory over Sporting Charleroi and Kortrijk knocked off Mechelen 2-1.