Byron Moore netted his fifth goal of the season as 10-man Crewe moved into the top three with a 2-1 home win over Bradford.
Moore netted just 60 seconds after City's Shane Duff had cancelled out Clayton Donaldson's opener to ensure the Bantams suffered their fourth defeat on the spin, while assistant referee Sian Massey had been withdrawn from her duties prior to kick-off.
The Alex played the entire second-half with 10 men after Donaldson was sent off for headbutting David Syers on the stroke of half-time.
The Railwaymen took the lead after 15 minutes when Shaun Miller's low centre was touched home by Donaldson.
Crewe looked to have paid the price for wasteful finishing when Duff levelled after Leon Osborne's 39th-minute free-kick arrived at his head via flick-ons from O'Brien and James Hanson.
But it took less than a minute for Moore to restore the Alex's lead with a cool finish when one-on-one with keeper John McLaughlin.
All the pre-match attention had been on assistant ref Massey's withdrawal following the fall-out from Andy Gray's sacking by Sky Sports.
But it was referee Kevin Wright who was under the microscope as the first half ended on a sour note.
Donaldson was rightly shown red by the official for headbutting Syers following a heavy challenge from the City midfielder.
And minutes later there was confusion when Gareth Evans was mistakenly shown a second yellow card when O'Brien clattered into Murphy.
Wright was made aware of his error after protests from Evans and his team-mates and the former Crewe trainee stayed on the pitch.
City tried to turn the screw on the Alex and Omar Daley and Syers both saw good efforts saved by Steve Phillips before the goalkeeper saved well at the feet of Jake Speight.
But Moore should have put Crewe out of sight when he failed to convert after being slipped in by Matt Tootle.
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