The late leveller cruelly cancelled out Josip Skoko's early strike after Stoke had deservedly led for the majority of the clash.
Despite fielding a depleted side, it was the injury-ravaged hosts who looked the more eager to break the ice.
Skoko spurned a golden opportunity with only four minutes gone before Carl Hoefkens thrashed over when really Stoke should have been celebrating an early lead.
But the lively Potters didn't have to wait much longer for a reward when Skoko nodded home in the 16th minute.
The Australian international steered into the abandoned United net after the usually reliable Paddy Kenny had left his station to flap at a cross.
The visiting side looked off the pace and were fortunate not to be facing Warnock's half-time rant with a larger deficit to overturn.
Hoefkens and Mamady Sidibe both wasted chances to double the tally - the Mali striker the more guilty of the two culprits.
The towering frontman shrugged off Chris Morgan's advances before blasting high and wide with the hard work already done.
One time Stoke City golden boy Ade Akinbiyi was thrown into the fray in the 58th minute to sharpen up a toothless United front line.
The visitors needed 23 second-half minutes to muster an chance but when it came it was more of a whimper than a signal of intent.
Webber turned on the turbos to dart into the City box but the resulting shot lacked accuracy and power.
Michael Tonge looked determined to haul the Premiership hopefuls back into the bout all on his own.
The fleet-footed midfielder skipped through the City reargaurd before letting off a rocket which left Steve Simonsen nursing sore fingers.
But there was nothing the City stopper could do five minutes later when Webber struck.
The nippy winger chased down a Craig Short through ball and kept his composure to sweep home his ninth of the campaign.