League Two Crewe knocked higher league Rotherham out of the FA Cup after Callum Ainley's late goal secured a comeback win.
The tie burst into life when Rotherham edged ahead through a classy finish from Will Vaulks, who curled a right-footed shot into the top corner.
And Rotherham were celebrating what they thought was their second goal when Kieffer Moore headed home Joe Newell's in-swinging corner on the stroke of half-time.
But an infringement was spotted before the corner was taken and Newell was ordered to retake the kick.
Crewe received some more unexpected assistance when they squared the tie straight after the break. Millers goalkeeper Richard O'Donnell was caught off his line as George Cooper drifted across a free-kick and Walker's flicked header found an empty net.
Vaulks went close to adding to his goal several times, and flicked the crossbar with a rasping drive, while Dave Richards did well to keep out a bullet header from Millers' leading scorer Moore.
But it was youngster Ainley who won it for Crewe in the last minute when he got on the end of a ball over the top and flicked a finish over O'Donnell, despite the efforts of Semi Ajayi to clear.
Match report supplied by the Press Association
