A much-spirited Spireites display saw a late Sam Morsy equaliser end the FA Cup second round tie 1-1 with Walsall in the wind at the Proact.
A new caretaker manager for the home sidebut there was no change in luck when the Saddlers took the lead on 19 minutes. Jason Demtriou got the the byline and crossed, the ball ricocheting off the luck-less Rickard Wood and into the net.
The second half saw Sylvan Ebanks-Blake denied what looked a penalty, a shot cleared off the line and by the underside of the crossbar.
The Spireites did finally get their leveller and a place in the hat for the third round, Morsy managing to scramble home an Ollie Banks freekick in the 90th minute from close range to send the tie into a second leg in the West Midlands.
It was an improved display under caretaker-manager Mark Smith, ending a run of four straight defeats.
Smith, taking charge of the team for the first time following the departure of Dean Saunders, opted for a 3-5-2 formation.
Sam Hird was on the right-hand side with Ian Evatt in the centre and Richard Wood on the left. Drew Talbot was handed a right wing-back role with Dion Donohue on the left. Liam O'Neil and Morsy started in the centre of midfield with Jay O'Shea in a more advanced role and Lee Novak and Ebanks-Blake in attack.
Novak put an early 20-yard effort off-target before Walsall struck.
The goal came from nowhere in the 19th minute when Demetriou's cross from the right-hand side of the area took a deflection off Wood and beat Tommy Lee at his near post.
There was a let-off for the visitors when keeper Neil Etheridge raced out of his area and cleared only as far as Novak who put his effort wide from distance.
George Evans carved out an opening for Walsall when he played a good one-two with Jordon Cook before firing wide of Lee's left-hand post.
Towards the end of the half, Wood 's tame header was easily gathered by Etheridge.
When Milan Lalkovic threatened to break through, Talbot made a great last-ditch tackle inside the area.
Novak then sent over a low cross that just evaded Ebanks-Blake as Chesterfield looked to force an equaliser.
Talbot again came to the rescue, clearing Paul Downing's header off the line.
Ebanks-Blake tried a shot on the turn which took a deflection wide.
Evans had a chance to extend Walsall's lead, but he put his free header over.
Chesterfield made a double substitution just after the hour-mark with Donohue and O'Shea going off and Dan Gardner and Ollie Banks coming on.
A third change was made five minutes later with Charlie Raglan taking over in defence from Wood.
The Spireites enjoyed a good spell and were unlucky not to equalise.
Gardner and Ebanks-Blake both had efforts cleared off the line and Ebanks-Blake also saw his shot hit the underside of the bar.
Ebanks-Blake then went down under a challenge inside the area, but referee Richard Clark turned down the penalty appeals.
Chesterfield's pressure finally paid off in the 89th minute when Hird hooked the ball into the six-yard box from Banks' free-kick and Morsy got the final touch from close range.
In a pulsating finish, Mantom hit the bar for Walsall with a free-kick that Lee did wonders to get an all-important touch on and Raglan went close with a header which was well saved.
Chesterfield: Lee (gk) - Wood (Raglan 70'), Evatt, Hird - Donohue (Gardner 64'), O'Neil, Morsy (c), O'Shea (Banks 64'), Talbot - Novak, Ebanks-Blake
Subs not used: Cairns (gk), Simons, Dieseruvwe, Ariyibi
Walsall: Etheridge (gk), Demetriou, O'Connor, Downing, Chambers (c), Sawyers, Henry, Lalkovic (Bakayoko 85'), Morris (Forde 61'), Cook, Evans (Mantom 74')
Subs not used: Taylor, Baxendale, MacGillivray, Preston
Chesterfield: Morsy 90'
Walsall: Demetriou 19'
Attendance: 4,126 (743 away fans)