Adam Armstrong hit a first-half hat-trick as Coventry romped to a 5-0 win at struggling Crewe.

While boss Tony Mowbray served a touchline ban, the Sky Blues ruthlessly punished a series of defensive errors from their hosts to coast into a four-goal lead by the interval.

Newcastle loanee Armstrong seized his first goal after a mistake by Ben Nugent in the 11th minute allowed Jacob Murphy to slip him clear to drive past Ben Garratt.

Ryan Lowe headed over and Marcus Haber failed to apply a firm connection with a header as Crewe rallied.

But Coventry hit two goals inside two minutes with Murphy firing a superb left-footer into the far corner for the second in the 27th minute.

And when Haber checked Romain Vincelot's run into the box with a trip, Armstrong converted the resulting penalty.

Armstrong took his tally for the season to 16 when he robbed James Jones and raced into the box to drive into the far corner.

The striker should have bagged his fourth soon after the restart, but prodded Murphy's cross wide from the edge of the six-yard box.

Reice Charles-Cook was off his line quickly to deny Jones a consolation before Murphy broke to fire the fifth into the bottom corner in the 85th minute.