Match ends, Walsall 0(5), Chesterfield 0(3).
Walsall came through a penalty shootout to beat Chesterfield and book an FA Cup third-round trip to former Saddlers boss Dean Smith's Brentford.
A dreary second-round replay between two well-matched League One sides took until extra time to come to life.
Walsall wasted five good chances in the extra 30 minutes to win it, but they converted all their spot-kicks to win 5-3 in the shootout.
Paul Downing struck the winning kick, with Sam Morsy missing for Spireites.
The Saddlers should have won before penalties, with Milan Lalkovic dragging his shot across goal and captain Adam Chambers having a shot deflected wide.
Kieron Morris clipped the top of the bar with a left-foot shot and was then denied by keeper Tommy Lee while James Baxendale missed from close range.
Walsall under new management?
Speculation is on the increase that Sean O'Driscoll is to be appointed as Walsall's new manager after Smith left for Brentford at the end of November.
The Saddlers have had three matches under the joint caretaker management team of physio Jon Whitney, goalkeeping coach Neil Cutler and the vastly experienced John Ward, who works with the academy.
But BBC WM 95.6 were reporting on Tuesday evening that the appointment of bookmakers' favourite O'Driscoll might be imminent.
The former Bournemouth, Doncaster, Crawley, Nottingham Forest and Bristol City manager has been without a club since losing his job as Liverpool assistant manager following Brendan Rodgers' sacking at the start of October.
Walsall winger Lalkovic, who played for O'Driscoll on loan at Doncaster three seasons ago, said on Twitter: "Worked with Sean and he gave me the chance in professional football. Think he would be fantastic replacement. Let's see..."
Walsall joint caretaker manager Jon Whitney told BBC Sport: "Overall, we deserved it and got our just desserts.
"It's great to have a cup run, but we'll put it to bed now as we really want to keep pushing on in the league.
"We didn't practise our spot-kicks, as we didn't want to put too much pressure on the lads, but they know what they're doing and they were five good penalties."
Chesterfield caretaker manager Mark Smith told BBC Sport: "We handled it really well for 90 minutes and we more than matched them.
"We looked a lot more solid and made life difficult for them and doing that against a team as good as Walsall can only stand us in good stead.
"I was pleased with the performance but we just need to be more ruthless when we get into good situations. We just lack that bit of confidence in the final third."
Walsall 1-0: Romaine Sawyers. Right foot bottom left corner. Keeper went wrong way
Chesterfield 1-1: Jay O'Shea. Right foot into bottom left corner
Walsall 2-1: Jason Demetriou. Right foot into bottom right corner
Chesterfield 2-1 (MISS): Sam Morsy. Right foot over bar
Walsall 3-1: George Evans. Right foot into bottom right corner, keeper went wrong way
Chesterfield 3-2: Lee Novak. Right foot placed into bottom right corner
Walsall 4-2: Milan Lalkovic. Right foot into bottom right corner
Chesterfield 4-3: Liam O'Neil. Right foot into bottom left corner
Walsall 5-3: Paul Downing. Right foot into bottom left corner
- 3TaylorBooked at 70mins
- 27EvansBooked at 87mins
- 8MantomSubstituted forLalkovicat 68'minutes
- 12FordeSubstituted forBaxendaleat 105'minutes
- 21CookSubstituted forMorrisat 85'minutesBooked at 95mins
- 6EvattBooked at 35mins
- 10O'SheaBooked at 67mins
- 5MorsyBooked at 56mins
- 24BanksSubstituted forDonohueat 103'minutes
- 7GardnerSubstituted forAriyibiat 45'minutes
- 26DieseruvweSubstituted forEbanks-Blakeat 77'minutes
- Charles Breakspear
- Shots on Target
Penalty Shootout ends, Walsall 0(5), Chesterfield 0(3).
Goal! Walsall 0(5), Chesterfield 0(3). Paul Downing (Walsall) converts the penalty with a.
Goal! Walsall 0(4), Chesterfield 0(3). Liam O'Neil (Chesterfield) converts the penalty with a.
Goal! Walsall 0(4), Chesterfield 0(2). Milan Lalkovic (Walsall) converts the penalty with a.
Goal! Walsall 0(3), Chesterfield 0(2). Lee Novak (Chesterfield) converts the penalty with a.
Goal! Walsall 0(3), Chesterfield 0(1). George Evans (Walsall) converts the penalty with a.
Penalty missed! Bad penalty by Sam Morsy (Chesterfield). Sam Morsy should be disappointed.
Goal! Walsall 0(2), Chesterfield 0(1). Jason Demetriou (Walsall) converts the penalty with a.
Goal! Walsall 0(1), Chesterfield 0(1). Jay O'Shea (Chesterfield) converts the penalty with a.
Goal! Walsall 0(1), Chesterfield 0. Romaine Sawyers (Walsall) converts the penalty with a.
Penalty Shootout begins Walsall 0, Chesterfield 0.
Second Half Extra Time ends, Walsall 0, Chesterfield 0.
Attempt missed. Liam O'Neil (Chesterfield) left footed shot from outside the box misses to the left.
Attempt missed. James Baxendale (Walsall) right footed shot from the centre of the box is close, but misses to the left.
Corner, Chesterfield. Conceded by Paul Downing.
Attempt saved. Kieron Morris (Walsall) right footed shot from the centre of the box is saved in the top centre of the goal.
Kieron Morris (Walsall) hits the bar with a left footed shot from outside the box.
George Evans (Walsall) wins a free kick in the attacking half.
Foul by Dion Donohue (Chesterfield).