Liverpool's stay might only last for 24 hours until overnight leaders Chelsea visit Aston Villa on Sunday.
Two goals from Xabi Alonso and Fernando Torres and one apiece by Ryan Babel and substitute Andriy Voronin helped the Merseysiders crush bottom team Derby.
Everton went second with a 2-1 victory at Bolton Wanderers thanks to a last-minute winner from Joleon Lescott. They trail Liverpool on goal difference.
Liverpool have 10 points, the same as Everton and Chelsea with Manchester City, who play at Blackburn Rovers on Sunday, next on nine.
Michael Owen scored in the 87th minute to give Newcastle United a 1-0 win over Wigan Athletic, who had Kevin Kilbane sent off.
Fulham stormed back from 2-0 and 3-1 down to force a 3-3 draw with Tottenham Hotspur at Craven Cottage while Middlesbrough beat Birmingham City 2-0.
West Ham United avenged last season's 6-0 defeat at Reading by winning 3-0 at the Madejski Stadium. The home team also missed a penalty.
Manchester United were playing Sunderland later on Saturday.