Jonjo Shelvey netted a hat-trick as Blackpool destroyed former manager Simon Grayson's 10-man Leeds on a miserable night for Paul Rachubka.
Leeds keeper Rachubka, a summer signing from Blackpool, was hauled off at half-time after three errors helped the visitors cruise into a 3-0 lead.
Lomana Lua Lua slotted home the Elland Road opener before Shelvey converted a retaken penalty after Tom Lees saw red.
Shelvey completed his treble either side of Lua Lua lashing in his second.
Signed after his release by Blackpool this summer, Rachubka has endured a tough introduction to the United first team since Andy Lonergan suffered a fractured finger in October.
Rachubka was publicly backed by boss Grayson after a mistake handed Coventry a 1-1 draw at Elland Road.
But his shaky form has continued and his manager was in less conciliatory mood on Tuesday, handing 18-year-old Alex Cairns his professional debut at the start of the second half.
Rachubka's problems began in the 13th minute when he could only parry Shelvey's shot into the path of Lua Lua, who knocked in a simple chance.
The keeper then dropped a routine catch, leading to Lees's dismissal for handling Ludovic Sylvestre's goalbound shot - Shelvey's resultant spot-kick was ordered to be retaken for encroachment but the on-loan Liverpool playmaker calmly stroked his second into the bottom corner.
Shelvey's second goal was also a gift as Rachubka dropped a speculative 25-yard Lua Lua shot at his feet as Blackpool opened a 3-0 lead inside the first 30 minutes.
Rachubka was booed as he received a backpass 10 minutes before half-time and Grayson replaced the keeper with Cairns at the interval.
Cairns, who has come through the Leeds academy, kept one Shelvey effort out but could do nothing to stop Lua Lua scoring his second when he cut inside Paul Connelly and fired into the top corner.
And Shelvey made an uncomfortable night for Grayson, against the club he left in acrimonious circumstances in December 2008, even worse when he completed his hat-trick after being played through by Martinez Angel with 12 minutes remaining.