Tottenham's bid to take over at the top of the Premier League was thwarted by a 1-0 defeat at West Ham.
Michail Antonio's first-half goal condemned Mauricio Pochettino's in-form side to a loss, their first away from home since the opening day.
Spurs knew victory would take them above Leicester to the summit for the first time this season, as well as send out a huge statement in the race for the title.
Instead they ran into a West Ham side determined not to give their fierce rivals a reason to celebrate in the final London derby under the lights at Upton Park.
The Hammers head to the Olympic Stadium next season but they will miss nights like this with their famous old ground rocking as they ended Tottenham's run of six straight wins.
Antonio will certainly miss the place -- all six of his goals for West Ham this season have come at home.
The latest arrived in the seventh minute, when Dimitri Payet swung in a corner and Antonio met it with a powerful near-post header which Hugo Lloris got a hand to but could not keep out.
Tottenham, having become the masters at coming from behind this season, had plenty of time to respond -- but this time they could not find a way back as Leicester's league cushion now sits at three points.
Arsenal suffered a major blow in the title race as struggling Swansea came from behind to win 2-1 at the Emirates Stadium.
The Gunners had a chance to close on leaders Leicester but lost at home to the Swans for the third time in four years to leave Arsene Wenger's men six points off top spot in third place.
Joel Campbell opened the scoring for the hosts in a game they dominated, hitting the woodwork three times over the course of the night, but it was Swansea who were left smiling as Wayne Routledge and Ashley Williams scored the goals to seal a win that moves them six points clear of the bottom three.
The visitors went into the game with the disruption of not having head coach Francesco Guidolin on the bench as he was hospitalised with a chest infection.
And his side, managed on the night by Alan Curtis, survived a near-onslaught of their goal as further profligacy from Wenger's Arsenal cost them dear.
Liverpool avenged Sunday's Capital One Cup final defeat to Manchester City, making short work of Manuel Pellegrini's men in a convincing 3-0 win at Anfield.
Adam Lallana got the scoring started for Liverpool in the 34th minute after a fairly dull opening half-hour. The Reds midfielder's low drive from 25 yards out was perfectly struck and found its way into the back of the net past a diving Joe Hart.
The goal brought the Anfield crowd to life and seemed to inspire Liverpool to push on against Man City, with Jurgen Klopp's men clearly on the front foot for the remainder of the first half.
The pressure paid off as former Man City player James Milner doubled the hosts lead, when he poked home from 12 yards after Roberto Firmino found him at the top of the penalty area to make it 2-0 ahead of half-time.
Pellegrini substituted Wilfried Bony for former Reds striker Raheem Sterling at half-time.
Liverpool continued to pressure the City defence in the second half and found their third when Lallana played the ball to Firmino in the penalty area and the Brazilian calmly curled a shot past Hart.
Juan Mata gave Manchester United's top-four hopes a timely shot in the arm, firing home a late free-kick as Watford's missed chances came back to haunt them in a 1-0 United win.
Doom, gloom and speculation about Louis van Gaal's future was replaced by positivity last week, with wins against Shrewsbury, FC Midtjylland and Arsenal complemented by teenager Marcus Rashford's remarkable emergence.
It had looked like United would be brought down to earth with a bump against Quique Sanchez Flores' impressive Watford outfit, only for captain Mata's free-kick to secure United a victory.
The result moves Van Gaal's men level on points with fourth-placed Manchester City, who have a game in hand, on a night when things could have been so different had the visitors turned large patches of dominance into a goal.
Stoke forward Xherdan Shaqiri's winner nine minutes from time consigned Newcastle to a sixth straight away loss in the league and kept them mired in the relegation zone after a 1-0 win.
The Magpies, back in action after 18 days off, arrived at the Britannia Stadium having not picked up a point on the road since a December 13 win at Tottenham, while they also had been eliminated from the FA Cup with a loss at Watford in January.
A point would have lifted them out of the bottom three, and they were on course to ensure a share of the spoils at the Britannia Stadium before Shaqiri popped up with a moment of magic in the Potters' 1-0 win.
The Swiss international collected substitute Mame Diouf's lay off and smashed a left-footed attempt beyond Rob Elliot in the Magpies goal.
It was enough to earn Mark Hughes' side a third win on the spin, yet they needed a fantastic one-handed save from Jack Butland to repel Seydou Doumbia in stoppage time and make sure of the points.
PA Sport contributed to this report.