Youth team keeper Josh Barrington could do nothing to prevent the hosts from scoring a 13th minute opener and he was also beaten after 32 minutes.
Jacob Hazel had a good shot well saved by former Chesterfield keeper Greg Fleming but the Spireites otherwise failed to create any real chances during the first 45 minutes.
The Spireites upped their game in the second-half and went close to scoring five minutes after the re-start when Fleming saved an effort from triallist Nathan Forbes-Swindells.
They did score just three minutes later when Matt Clarke and Hazel linked up to release Jonathan Wafula who squared to Josh Scully and he fired into the top corner of the net.
The equaliser came in the 62 minute when Jack Waddle played the ball in from the right and Forbes-Swindells beat his marker before firing from right to left across Fleming.
As Chesterfield went in search of a winner, youth team player Cormac Noel forced a great save from Fleming.
At the other end of the pitch, Barrington also made a couple of good saves to keep the Mariners at bay.
Coach John Dungworth summed up the performance by saying: "We applied ourselves well in the second-half and finished the stronger team."
Striker Forbes-Swindells was joined by two other triallists, Oscar Radford and Chris Jones.
Line-up: Barrington, Jones, Radford, Whittaker, Clarke, Noel, Wafula (Fereday 85), Scully, Waddle, Forbes-Swindells, Hazel