Leicester's Jermaine Beckford and Millwall's Darius Henderson both completed hat-tricks to send their respective sides into the fourth round of the FA Cup.
A George Boateng own-goal and three goals from Beckford inspired the Foxes to a 4-0 humbling of their east midlands rivals Nottingham Forest.
Meanwhile, goals from Henderson and on-loan Harry Kane were enough for the Lions, who finally found their goalscoring touch to see off Dagenham 5-0 in their third-round replay.
Boateng set the tone for a dire night for the Reds, clipping into his own net following a goalmouth scramble, before Leicester took control of their own destiny through the mercurial Beckford.
The summer signing from Everton headed his first goal in 11 outings for the Foxes before sending a heatwave through the bitterly-cold King Power Stadium with two close-range finishes after the break.
Forest were not without their fair share of chances in the opening half, and Robbie Findley's poor miss with the goal gaping summed up a dreadful evening for Steve Cotterill's side.
The victory represents a morale-boosting second home win in six attempts for Nigel Pearson's side, but heaps further pressure on relegation-threatened Forest, who sit 22nd in the npower Championship.
For Millwall, top scorer Henderson found the net for the first time since November and Tottenham loanee Kane grabbed his first goals for the club as they dispatched their League Two opponents at the second attempt.
Victory came as a huge relief to manager Kenny Jackett, who had seen his side score just once in their previous eight outings and thumped 6-0 by Birmingham just three days ago to leave them embroiled in the Championship relegation battle.
It also meant Millwall made it through to the fourth round - and a home tie with Southampton - for only the third time in eight attempts since they lost the 2004 final to Manchester United.
Source: PA
Source: PA