Tottenham's Christian Eriksen scored within 11 seconds on Wednesday to overshadow Alexis Sanchez's Premier League debut for Manchester United, while Chelsea crashed to a 3-0 defeat by Bournemouth at Stamford Bridge.
Manchester City ignored the carnage around them to march serenely on, widening their lead to an enormous 15 points with a 3-0 victory at home to West Brom with just 13 games still to play.
The build-up to Wednesday's matches was dominated by late moves in the transfer window but Spurs ensured the focus switched back to the pitch immediately, stunning Jose Mourinho's men with a performance full of attacking verve in a 2-0 win.
Chelsea, who earlier announced the signing of Olivier Giroud from Arsenal, conceded three second-half goals while Theo Walcott scored twice for his new club Everton in a 2-1 win against Leicester.
"We always try to be aggressive from the beginning," said delighted Spurs boss Mauricio Pochettino. "Our aim is to be focused from the beginning. You can win a game if you're ready to fight. It was massive to be up early in the game."
The painful defeat for United realistically ends any lingering hopes they may have harboured of catching runaway leaders City.
Mourinho signed Sanchez this month to bolster his attacking options but Spurs caught the visitors cold at a packed Wembley, Eriksen opening the scoring from the kick-off following a long ball from inside the Tottenham half.
The goal, timed at 10.48 seconds, was the first United have conceded in 2018 but despite some bright moments of their own they were 2-0 down just before the half-hour after Phil Jones lashed the ball into his own net.
Tottenham, who announced the signing of Moura from Paris Saint-Germain shortly before kick-off, were a constant threat and had multiple chances to stretch their lead.
Mourinho threw on Juan Mata and Marouane Fellaini in the 63rd minute but bizarrely took Fellaini off just seven minutes later, replacing him with Ander Herrera. The Belgium international took off his shirt and marched straight down the tunnel.
The impressive win for Spurs puts them right back at the heart of the hunt for a Champions League qualification spot, just two points behind fourth-placed Chelsea.
Pochettino's men were further buoyed by the defeat for Chelsea, who fielded only Pedro up front, showing their need for more firepower. Callum Wilson, Junior Stanislas and Nathan Ake scored the goals for Bournemouth.
It was business as usual for Guardiola's City, who handed a debut to USD 57 million defender Aymeric Laporte, who only signed for the club from Athletic Bilbao on Tuesday.
City struck through Fernandinho midway through the first half and doubled their lead through Kevin De Bruyne in the second half before Sergio Aguero struck late on.
City earlier opted out of a bid for Leicester's Riyad Mahrez, with reports putting the transfer package at £95 million, after ending their chase of Sanchez earlier in the transfer window, due to slam shut at 2300 GMT.
In other results on Wednesday, Newcastle drew 1-1 with Burnley, Southampton drew 1-1 at home to Brighton and Stoke were involved in a goalless stalemate with Watford.
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