Peter Vincenti grabbed a late equaliser as Aldershot all but ended Northampton's slim play-off hopes after a 1-1 draw at Sixfields.
It was Northampton's fourth consecutive draw and once again they failed to hold on to their advantage, this time given to them by Ben Tozer in the first half.
And to make matters worse Cobblers had striker Shaun Harrad sent off and will now face suspension.
Northampton took an 18th minute lead against the run of play when Tozer turned the ball home from close range after Aldershot failed to clear an in-swinging corner from Michael Jacobs.
Substitute Frances Laurent missed a good opportunity to double Northampton's advantage before Aldershot deservedly drew level in the 78th minute when Vincenti turned the ball home at the far post from Alex Rodman's cross.
Four minutes later Harrad received a straight red for kicking out at Anthony Charles but Northampton could have won it in the 85th minute when Josh Walker was denied by keeper Jamie Young. Aldershot almost grabbed a late winner when Rodman fired wide from the edge of the box with two minutes of normal time remaining.
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