Simon Walton capped a thrilling comeback for Crewe in a 3-2 win as Northampton suffered their first away defeat since November.
Crewe took the lead in the 16th minute after John Johnson tripped Joel Grant on the edge of the box, with Ashley Westwood curling the free-kick low around the wall and into the bottom corner of the net.
Cobblers stopper Billy Lumley denied Luke Murphy and Crewe's Steve Phillips somehow kept out Liam Davies' rasping volley as both keepers were called into regular action.
Phillips did well to keep out Davies' long-range effort but he could not prevent Ryan Gilligan's shot finding the net on the stroke of half-time.
The visitors edged ahead 12 minutes after half-time, Adebayo Akinfenwa turning and despatching a side-footed finish into the bottom corner.
But Westwood levelled matters in the 65th minute with a low angled finish across Lumley. And Crewe completed the turnaround when Walton beat Lumley with an unstoppable 30-yard half-volley four minutes later.
The visitors looked to have been denied a late equaliser when a Gilligan's header appeared to have crossed the line before being cleared by a defender but referee Peter Quinn waved play on.
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