De Sutter scored in the 50th minute and substitute
Lokeren remains third in the table, but now trails second-placed Zulte-Waregem by four points.
Zulte-Waregem was a comfortable 2-0 winner over Lierse, which slipped a place to 15th in the 16-team league.
Karel D'Haene put Zulte-Waregem on its way with a 28th-minute opener, and its second goal arrived after 52 minutes with Franck Berrier the scorer.
Beerschot nudged ahead of Lierse after a goalless draw at home against Mons.
With the race for top-six places warming up, Genk, which currently occupies sixth place, fell to a 2-1 defeat against pursuer KV Mechelen.
Mechelen, which climbed to seventh place with the win, four points behind Genk, went ahead through
In lower mid-table, Waasland-Beveren withstood the dismissal of
Blondelle was ordered off in the 56th minute, but
Anderlecht has sacked John van den Brom after some indifferent form in the Jupiler Pro League with assistant boss Besnik Hasi appointed the new head coach.