Jay O'Shea's first-half belter and last-second finish secured Chesterfield three priceless points with a 2-0 win in a necessarily strong defensive effort from the visiting Spirietes.After a good start from the visitors a O'Shea peach of a volley gave the Spireites the lead, which they were able to keep to the break despite mounting Millwall pressure.
The second half was a backs-to-the-wall effort, but good goalkeeping from Tommy Lee and stout defending kept the Lions at bay and O'Shea's late second on the break sent the 508 travelling Spireites back up the M1 happy.
The first half started even as both teams battled well in the middle of the park, but it took no more than four minutes for Chesterfield to create their first chances of the game.
Gboly Arybi, who came into the squad for the injured Lee Novak, put in a great ball which was met by Ian Evatt in the box, but from six yards the defender headed straight at the keeper.
Chesterfield were attacking with high tempo causing the Millwall defenders problems, this time Dan Jones whipped in one of his trademark crosses but Spanish midfielder Angel headed just wide.
With 16 minutes on the clock the Spireites were starting to dominate possession. A Millwall clearance dropped to O’Shea outside the area and the midfielder volleyed home a spectacular effort into the bottom corner.
It took a while for both teams to create any clear-cut chances after the goal, Chesterfield’s defence was doing well to withhold heavy pressure from the hosts. The Lions were putting crosses in at every opportunity but none of them were falling to the right players.
Although Millwall were dominating possession it was Chesterfield who created the next chance, this time the lively Sam Morsy was put through one-on-one with the keeper but Jordan Archer managed to block it.
Chesterfield again were creating the better chances, this time Millwall lost the ball in the middle of the park and was collected by Angel who put Gardner through on the wing, he tried to play a switch to Sylvan Ebanks-Blake but the ball was cleared for a corner.
Millwall started the second half brightly with much of the play coming from the wings. Fred Onydeinma played a fine one-two with Shaun Cummings and his cross was met by Jimmy Abdou but his shot was well blocked by Evatt.
Aryibi’s pace was proving too much for the Millwall defence, his well-timed cross was met by Ebanks-Blake but his shot was scuffed straight into the 'keeper's hands.
Millwall were beginning to dominate the game, substitute Aiden O’Brien played a ball into Onyedinma who stretched but couldn’t meet it.
Five minutes later Chesterfield were down the other end trying to cause trouble themselves. Ebanks-Blake was put in but had other ideas and passed it to O’Shea but his weak effort found the 'keeper.
It was backs-to-the-wall stuff as Millwall were adding pressure, putting many crosses in but none of them meeting anyone in a blue shirt.
A first real chance for Millwall came 15 minutes before the end as striker Abdou met a floating cross, shot from eight yards, the ball deflected off a Spireites defender but Tommy Lee made a fantastic one-handed save to deny Millwall an equaliser.
Millwall were starting to dominate on chances, Paris Cowan-Hall put in O’Brien who found Onyedinma but yet again the striker wasted another chance from five yards out.
Five minutes were added on at the end of the second half, the Spireites were doing all they could to see the game out. Armand Gnanduillet had a great chance to make it 2-0 to the Spireites but curled his effort just wide.
Every attack saw Chesterfield go to the corner, with the home fans getting more and more impatient with their team.
With just less than 30 seconds left on the clock there was still one more chance for Chesterfield. Millwall failed to clear their lines and substitute Mani Dieseruvwe managed to keep the ball in, found O’Shea in the box, the midfielder ran past two men and his shot deflected past Archer into the back of the net, the points now secured for the visitors.
Millwall: Archer (gk), Cummings (Marquis, 86'), Craig (c), Gregory (O'Brien 46'), Onyedinma, Nelson, Beevers, Morison, Powell (Cowan-Hall 75'), Thompson, Abdou
Subs not used; Forde (gk), Williams, Upson, Webster
Chesterfield: Lee (gk) - Jones, Evatt, Hird, O'Neil - Morsy (c), Angel, Ariyibi (Dieseruvwe 72'), O'Shea, Gardner (Raglan 87')- Ebanks-Blake (Gnanduillet 72')
Subs not used: Cairns (gk), Humphreys, Harrison, Banks
Chesterfield: O'Shea 17', 90+5
Attendance: 8,374 (508 away fans)