Rafael Benitez's plan to protect his Chelsea stars ahead of the FA Cup tie with Manchester United backfired as the Blues slumped to a 2-1 defeat at struggling Southampton on Saturday.
Gareth Bale helped Tottenham seize the initiative in the race for Champions League qualification by scoring another spectacular goal.
Titus Bramble's own goal earned United an English-record 25th win from 30 league games and kept the team 15 points clear of Manchester City, which thrashed Newcastle 4-0 to tighten its grip on second place.
Spurs leapfrogged Chelsea into third place thanks to a 2-1 victory at Swansea, with Bale's sublime curler proving decisive, and the European champions' 2-1 loss at Southampton.
Fifth-place Arsenal stayed in touch with its London rivals in the battle for a top-four place by beating Reading 4-1.
Relegation-threatened West Ham and Wigan also won.