Chesterfield have booked an FA Cup tie with Scunthorpe United on Tuesday by beating MK Dons 1-0 in their replayed second-round match tonight.
Gary Roberts scored the only goal of the game as the Spireites repeated their narrow victory in the original fixture at Stadium MK on December 6.
The Football Association ordered the match to be played again after Chesterfield were found to have fielded an ineligible player - Wolverhampton Wanderers loanee Georg Margreitter - but there was to be no change in the result.
Only three places, albeit 12 points, separate the two teams in the League One table, and it was a even contest from first whistle to last as they had 50% possession each and shared the game's best chances.
Benik Afobe and Chesterfield striker Eoin Doyle had each squandered an early chance for their side in what was an uneventful first half until Roberts buried from the centre of the box after Doyle's pass on 41 minutes.
Dean Bowditch missed for the Dons with a close-range header two minutes after the break, but Chesterfield twice came close to extending their advantage through misfiring forward Armand Gnanduillet.
Spireites keeper Tommy Lee had to be at his best to keep his side ahead when Bowditch tried his luck again, and George Baldock wasted a good final chance to equalise when he dragged wide in stoppage time.
Chesterfield have only a four-day wait until they face another League One rival, Scunthorpe, in the next round.
