Late winner keeps Ajax in contention
Alderweireld's venomous strike was too much for Ricky van den Bergh who had swapped his midfield position to go in goal with 15 minutes left after keeper Barry Ditewig had been sent off.
Twente Enschede, 2-0 winners at VVV Venlo on Saturday, are top with 77 points with four matches remaining.
Ajax are second on 73 points, one more than PSV Eindhoven who won 1-0 at Willem II Tilburg. Balazs Dzsudzsak converted an 81st-minute penalty to earn PSV victory.
Fourth-placed Feyenoord, on 56 points, were held to a goalless draw at home by NAC Breda while substitute Samuel Armenteros hit a late double for Heracles Almelo who beat NEC Nijmegen 2-0 and moved up to sixth with 49 points.