Liverpool swept to the top of the Premier League with an emphatic 6-1 victory over Watford at Anfield.
The Reds piled on the pressure in the early stages, with the visitors grateful to goalkeeper Heurelho Gomes, who denied Lucas Leiva from close range, but the home side broke through after 27 minutes when Sadio Mane glanced a superb header past Gomes following a short corner routine.
They added another before half an hour had been played, Coutinho making space on the edge of the area before smacking the ball home. The Hornets lost Gomes to injury before the break, bringing Costel Pantilimon on in his place, and the stand-in was soon beaten as Emre Can sealed the points before half-time, heading home unmarked.
Liverpool had scored five before the hour mark as the Watford defence collapsed, Firmino and Mane left alone to turn in low crosses from close range.
A well-taken goal from Daryl Janmaat at least gave Watford something to show for their afternoon's work but Georginio Wijnaldum followed up a parried effort from substitute Daniel Sturridge to make it six in the closing seconds.
Manchester United and Jose Mourinho returned to winning ways and deepened Swansea's problems with a 3-1 victory at the Liberty Stadium.
Wayne Rooney, back in the starting Premier League lineup, came close to giving United the lead early on when he made space for a low shot that bent narrowly wide of the post.
United were enjoying plenty of possession, with Michael Carrick prominent, and took the lead against the struggling Swans with 15 minutes on the clock as Paul Pogba blasted home a superb volley when a clearance fell to him on the edge of the area.
The visitors soon doubled their advantage as Zlatan Ibrahimovic ended his recent goal drought and registered the Premier League's 25,000th strike when his low shot got away from Lukasz Fabianski, and he added another just before the half-hour mark.
The home side pulled a goal back after 69 minutes when defender Mike van der Hoorn headed home from close range, but United won easily.
A Harry Kane penalty stopped Arsenal going top of the Premier League as Tottenham Hotspur earned a 1-1 draw in the North London derby.
The Gunners took a first-half lead through Kevin Wimmer's own goal but Kane, on his return from injury, ensured a share of the spoils for the visitors with a second-half spot-kick.
Spurs created the better chances in the early exchanges, with Kane's diving header from a Christian Eriksen cross going narrowly wide.
Arsenal began to grow into the game and Theo Walcott struck the inside of the post with a ferocious effort, but Spurs came closest to winning it when Eriksen's free-kick bounced past everyone and hit the far post.
Matt Phillips scored the winner as champions Leicester City lost 2-1 to West Bromwich Albion at the King Power Stadium, ending the Foxes' long unbeaten home record.
What had been a dull game before the break exploded into life after it thanks to two goals in three minutes. Phillips set up West Brom's opener when his fine cross was headed home by James Morrison, but the Foxes were level when Mahrez provided the opening for Islam Slimani to head the equaliser.
But Phillips profited from a Danny Drinkwater mistake to win it for Albion, pouncing on the Leicester man's woeful attempt to pass the ball back to his goalkeeper to run on and dink a finish home.
Hull City gave their free-falling fortunes a much-needed boost as they came back from a goal down to beat Southampton 2-1 at home.
The Tigers got off to the worst of starts, conceding a penalty after only seven minutes when Curtis Davies fouled Maya Yoshida, and Charlie Austin blasted the ball down the middle to put the Saints in front.
Hull keeper David Marshall denied Austin a second when he blocked his attempt from an angle as time ran out, but the game turned around in dramatic finish with two goals in as many minutes after the break. Robert Snodgrass levelled when he finished superbly from 12 yards, and then defender Michael Dawson came forward to flick home a header from a free-kick.