Northampton extended their unbeaten run to seven games but failed to close the gap on Chesterfield after the two sides fought out a stalemate at Sixfields.
Neither keeper had a serious save to make in the whole 90 minutes as both sides failed to find their form in the final third.
Northampton had the better of the first-half chances, with Peter Gilbert firing a 25-yarder just wide in the 37th minute, and two minutes later top scorer Adebayo Akinfenwa headed over from a Luke Guttridge cross.
Chesterfield's best chance of the half came on the stroke of half-time when the much-travelled Barry Conlon headed over from an Ian Morris free-kick.
Northampton looked the more likely to score in the second half, and substitute Courtney Herbert failed to capitalise on some hesitancy in the Chesterfield defence on the hour-mark.
Fellow substitute Stephen O'Flynn also had an opportunity to win it for Cobblers in the 76th minute, while Herbert had a second chance in the 89th minute, but he shot over from a good position.
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