The Spireites looked set for a comfortable victory at the break as they led 1-0 and had dominated proceedings.
But then Morecambe changed their system for the second half and the game itself changed shape dramatically.
Suddenly Morecambe looked to have a threat and few could argue that they did not deserve their 73rd minute equaliser in the end.
Chesterfield were by far the better team in the first 45 minutes and they could have taken the lead after just two minutes.
Influential skipper Peter Leven broke up a Morecambe move on the edge of his own box and played in Jamie Ward behind the defence.
Ward looked sure to score but was denied by Morecambe keeper Scott Davies who had an excellent game.
Derek Niven then came close to scoring for Chesterfield on two occasions with late runs into the box, before Lee Richardson's side took a deserved lead on 35 minutes when Steve Fletcher lashed home the loose ball from the edge of the box with a shot that flew into the top left-hand corner of Davies' goal.
Ward had a good chance to double the advantage two minutes later but was again denied by the impressive Davies.
Morecambe boss Sammy McIlroy sacrificed a forward for a midfielder in the second half and it proved a stroke of genius.
The extra body in the centre of the park stopped Chesterfield's supply line and Morecambe forged chances of their own.
Damien Allen should have scored just a minute into the second period but, with time and space eight yards out, he volleyed his effort horribly wide.
Chesterfield hit back with skipper Leven seeing a low drive superbly saved by man-of-the-match Davies, before Morecambe took control of the game.
Wayne Curtis hit the post with a fine strike on 62 minutes and the same player was involved as Morecambe levelled on 73 minutes as he slid in Matty Blinkhorn, who beat Barry Roche with a low drive.
Blinkhorn then volleyed into the side-netting and Curtis saw a screamer deflected inches over by Chesterfield sub Lloyd Kerry, before Morecambe keeper Davies saved from the same player in the final minute as the game ended all square.