A round-up of Sunday's Premier League action.
Arsenal's controlled 1-0 win at London rivals Chelsea on Sunday offered the strongest evidence this season that the Gunners can finally challenge again for the title that has eluded them for nearly 20 years.
Arsenal players and fans celebrated loudly after the match at Stamford Bridge, knowing the three points not only took them back above Manchester City at the top of the table but also confirmed they can hurt the Premier League's heavyweights.
The north Londoners claimed the only goal of the game when defender Gabriel stabbed home after a corner eluded a string of Chelsea players, but the narrow victory margin masked their superiority over the 90 minutes.
The Gunners' only league defeat of the campaign was in September away to one of England's traditional top-six clubs, Manchester United, drawing criticism that their strong start to the season was based on wins against lesser opposition.
Although they have beaten local rivals Tottenham Hotspur and Liverpool since then, both those wins were at home, adding to the sense that Sunday's victory in West London was a milestone in their season.
Arsenal now have 34 points after 13 games, the most they have racked up at this stage of the season since the Premier League was launched and are two points ahead of second-placed Manchester City.
For Chelsea, a second defeat in a row after last weekend's 4-1 drubbing by Brighton & Hove Albion underscored the challenge facing coach Graham Potter who is two months into his time in charge of the Blues, and 13 points adrift of the Gunners.
Salah strikes twice as Liverpool down Spurs
Liverpool forward Mohamed Salah cleverly fashioned one goal and was gifted another as the visitors won 2-1 at Tottenham Hotspur despite a battling display by the home side after the break in their Premier League clash.
Egyptian Salah opened the scoring after 11 minutes with a precise finish while his second goal just before half-time was a gift from Eric Dier who miscued a header straight to him.
Tottenham had their moments, with Ivan Perisic hitting the woodwork in each half, and they could have had a penalty when Ryan Sessegnon was bundled over by Trent Alexander-Arnold.
In the second half, Spurs raised their game, boosted by Dejan Kulusevski returning from injury off the bench late on. He had an instant impact as he fed Harry Kane who scored in the 70th.
But Liverpool weathered the storm to claim the win and end a run of two Premier League defeats, leaving them eighth on 19 points after 13 games. Spurs slipped to fourth on 26 from 14.
Liverpool took the lead when Salah controlled a pass from Darwin Nunez inside the area, turned and expertly fired a low shot into the corner with his left foot.
Spurs were under pressure but four minutes later they almost equalised when Kane broke down the right and crossed to the impressive Perisic whose header hit Alisson and then the post.
Salah was handed his second goal on a plate after 40 minutes when Dier's attempted header came off his shoulder from a long kick by Alisson and the Egyptian dinked the ball past Lloris.
Tottenham started the second half much brighter, as they usually do, and Perisic was desperately unlucky to hit the bar when he met a cross to the far post from Dier.
A huge cheer greeted Swede Kulusevski when he made his first appearance for seven weeks in the 68th and two minutes later he set up Kane who fired home to rally the Spurs fans.
But despite a late Tottenham onslaught, including a close-range header from Rodrigo Bentancur, Antonio Conte's side could not find an equaliser and Liverpool left with the points.
Crystal Palace earn rare away win at West Ham
Michael Olise scored a 94th-minute goal as Crystal Palace earned their first away win of the season with a 2-1 Premier League victory over a sloppy West Ham United on Sunday, but the home side were aggrieved that they did not get a late penalty.
Olise netted the decisive goal when his shot from the edge of the box took a big deflection and looped into the back of the net to secure Palace's first away success since April.
They climbed to ninth in the table with 19 points from 13 games, while West Ham are 15th with 14 points from 14 matches.
Said Benrahma had put West Ham ahead in the 20th minute with a thunderous strike from outside the box, but the home side lacked rhythm in a poor performance that will be frustrating for manager David Moyes whose team were booed off at the end.
West Ham defender Thilo Kehrer's error gifted possession to Eberechi Eze and he slipped Wilfried Zaha in on goal, the latter’s powerful shot arrowing into the net in the 41st minute.
With the score at 1-1, West Ham thought they should have had a chance to potentially win the game with 10 minutes left when substitute Michail Antonio appeared to be pulled back in the box by Marc Guehi.
Referee Paul Tierney awarded a spot-kick but changed his decision after a review. Boos from the home fans rang around the stadium at the final whistle.
Aston Villa end Manchester United's unbeaten run
Aston Villa manager Unai Emery tasted victory in his first game in charge as his side beat Manchester United 3-1, the visitors' first defeat in 10 matches in all competitions.
Former Arsenal boss Emery was given a warm welcome by home supporters ahead of the match, and he could not have wished for a better start to life back in the Premier League as Villa raced into a two-goal lead inside 11 minutes.
Leon Bailey arrowed a strike into the bottom corner to give Villa the lead, before Lucas Digne curled a sublime free-kick past the despairing dive of United goalkeeper David de Gea, much to Emery's delight on the touchline.
United improved a great deal as the half wore on, creating several openings before Luke Shaw's strike took a huge deflection off Jacob Ramsey and found the net on the cusp of halftime to give the visitors hope.
Those hopes were quickly dashed, however, as Ramsey made amends, finding the top corner four minutes into the second half to restore Villa's two-goal advantage.
Tempers flared as the match reached its climax, but United could not muster a comeback, losing for the first time at Villa Park in the league since 1995 to stay fifth in the standings as a well-deserved victory lifted Villa to 14th.
It was a run of 23 games that United had gone unbeaten at Villa Park in the Premier League, the longest undefeated away run a team has had against another in English league history, but the writing was on the wall from the start on Sunday.
Ramsey set Jamaican winger Bailey through on goal and he rifled home the opener, the first goal United have conceded from open play in over 12 hours of football in all competitions.
Things went from bad to worse for the visitors when Ramsey won a free kick, and full-back Digne stroked an unstoppable shot into the net.
United finally found their feet just after the half-hour mark, with Emiliano Martinez in the Villa goal was forced into two fine saves to deny youngster Alejandro Garnacho and captain for the day Cristiano Ronaldo.
Shaw's strike did not look like it was heading for the net, but the huge deviation off Ramsey's back gave Martinez no chance.
That stroke of luck proved to be only a consolation for a below-par United, as Ramsey, who had run United ragged all afternoon, fired home Ollie Watkins's pass to restore Villa's two-goal advantage.
Each of the previous nine managers to face United in their first Premier League match in charge of a team had all lost, with the Spaniard becoming only the fourth to get off to a winning start with a new side against the 20-times top-flight champions.
Ruthless Newcastle trounce Southampton
Newcastle United produced another ruthlessly impressive display in a 4-1 Premier League win over struggling Southampton at the St Mary's Stadium on Sunday, with Miguel Almiron bagging his seventh goal in as many games.
Quickfire second-half goals from substitute Chris Wood and Joe Willock all but sealed a fourth straight win for Newcastle, with Bruno Guimaraes adding a late flourish after Romain Perraud's consolation goal for the hosts.
The result lifted Newcastle, who extended their unbeaten run to nine matches, provisionally into third place on 27 points from 14 games, before Tottenham Hotspur's game against Liverpool later on Sunday.
Southampton remained 18th on 12 points after a sixth defeat in nine games, having dropped into the relegation zone after Leicester City's win over Everton on Saturday.
After a frantic and fast-paced opening half-hour, a quick Newcastle break put Almiron through on goal and he dribbled past Ainsley Maitland-Niles before calmly rolling the ball past goalkeeper Gavin Bazunu with 35 minutes on the clock.
Newcastle made a quiet start to the second half but doubled their lead with their first attack after the break when Jacob Murphy found Wood in the box and the substitute fired a brilliant shot into the bottom corner after 58 minutes.
Kieran Trippier slipped a delightful through ball for Willock to latch on to and poke past Bazunu four minutes later before Perraud pulled back a goal in the 89th minute in stunning fashion, cutting inside the sliding Dan Burn and curling his shot into the net.
The visitors were relentless, however, and restored their three-goal advantage in the first minute of stoppage time when Allan Saint-Maximin set up Guimaraes outside the box and the midfielder curled a brilliant effort past the diving Bazunu.