Chelsea's four-match winning run in the Barclays Premier League ground to a spectacular halt as struggling west London rivals QPR won 1-0 to claim their first victory at Stamford Bridge for two decades.
Shaun Wright-Phillips, an early substitute for the injured Junior Hoilett, struck a brilliant 78th-minute winner against the club he left in 2008 to further erode the Blues' fading title hopes.
Wright-Phillips' second goal of the season topped a fine performance from QPR that was a vast improvement on Sunday's tame home surrender to Liverpool.
It was a crucial victory that ended their three-match losing run, giving Harry Redknapp his second win since becoming manager last month, and while they remain bottom of the table on goal difference the result invigorated their relegation battle.
Victor Anichebe scored the winner as Everton's 2-1 victory plunged Newcastle deeper into crisis as a difficult day on Tyneside ended in depressing style.
The striker needed just two minutes to steer home Nikica Jelavic's cross to complete a comeback which saw the Toffees condemn the Magpies to a ninth defeat in 11 league games.
That was the last thing manager Alan Pardew needed with leading scorer Demba Ba finalising his transfer to Chelsea, while Mathieu Debuchy - sitting in the stands as he prepared to complete his move from Lille - was left in little doubt about the fight into which he is about to be plunged.
It had all started so well for the home side when Papiss Cisse headed them in front with just 72 seconds played, but Leighton Baines' stunning free-kick cancelled out the advantage two minutes and Anichebe won it to move the Toffees within two points of Chelsea, who have a game in hand.
Liverpool may have brought in reinforcements to ease the apparent burden on striker Luis Suarez but their leading scorer appears not to notice or care as he hit two to help beat Sunderland 3-0 at Anfield.
With new team-mate Daniel Sturridge in the stands, the Uruguayan took his tally to 15 in 19 league matches - the last Reds player to reach that total was Fernando Torres in 2009-10, scoring 18 a year after they almost won the title.
Raheem Sterling opened the scoring with a well-taken lob over goalkeeper Simon Mignolet as Liverpool began the new year with a home victory after recording just six in the league in the whole of 2012.