Chesterfield and Northampton Town go into the break with the scores level after Dan Gardner's goal cancelled out Darren Carter's penalty.
Carter's penalty put Northampton in front after Hallam Hope was brought down by Chesterfield keeper Tommy Lee on the edge of the six-yard box.
Chesterfield soon equalised through Gardner when he fired in following Gary Roberts's quick free kick.
Conditions worsened throughout the half, with several patches of standing water emerging on the pitch.