There are still 10 first-round matches to be completed and the tournament is scheduled to conclude Saturday. The original schedule had called for the second round to be played Wednesday.
Rain, however, is predicted for Brussels through the week.
Among the matches that had been on Tuesday's schedule was one in which fourth-seeded Sloane Stephens against Tsvetana Pironkova. They started play Monday but the match was suspended because of darkness tied 2-2 in the third set with Stephens about to serve.
No. 1-seed Caroline Wozniacki, who has a first-round bye, is the defending champion.