Strikes from Alex Davey and Lyle Taylor in the first half looked set to see the Spireites' run in the competition coming to an end, but an Eoin Doyle penalty and a late Jay O’Shea strike completed a stunning comeback to earn a 2-2 draw.
Scunthorpe 2-2 Chesterfield
FA Cup Third Round Proper
Tuesday 6 January
Glanford Park, Scunthorpe
Winners receive £67,500
"My players are brilliant," said Cook afterwards. "I see my lads come in on a morning, do the gym work, go to training, do the fitness, do the nutrition.
"And I know when it gets to later stages of games we are going to keep going. We are fit."
Despite falling behind, Cook explained the importance of his side’s ability to produce late goals.
"Good teams score late goals. We only needed to get one to give our supporters a massive lift, and that engaged us then to get home. The only disappointing thing is that we felt we deserved more than we got."
And speaking to Chesterfield-FC.co.uk, the 47-year-old also heaped praised on the 1,663 supporters who travelled to back his men in Lincolnshire.
"The supporters have big belief in us at the minute, and the second half performance has justified that, and they’ll go back to Chesterfield happy," he added.
"You represent your club as a manager and you’re always proud of your team no matter what. If I can’t stand up for them then no one can."
The FA Cup Third Round replay between Chesterfield and Scunthorpe will take place at the Proact Stadium on Tuesday 13 January, kick-off 7:45pm. The winners will travel to Derby County in the next round.
