Manchester City stretched their perfect start to six games by beating Nottingham Forest 2-0 to remain two points clear of Liverpool, who defeated West Ham 3-1.

Arsenal's title ambitions were damaged by Son Heung-min's double to salvage a point for Tottenham as the north London derby ended 2-2, leaving both sides four points off the top.

And it was another weekend to forget for Chelsea as they lost 1-0 at home to Aston Villa to sink to 14th.

AFP Sport looks at three talking points from the Premier League weekend:

Promoted trio finding it tough

Sheffield United suffered their worst-ever league defeat as Saudi-backed Newcastle ran riot at Bramall Lane.

But the Blades are not the only club struggling to bridge the financial and quality gap between the Championship and the Premier League.

Burnley and Luton's promotion parties seem a distant memory as they sit alongside Sheffield United in the bottom three.

After a combined 16 games this season, none of the three have even collected a win, with the trio all having just one point on the board.

Luton were the last to get off the mark as they drew 1-1 with Wolves on Saturday.

But even that felt like a missed opportunity for the Hatters after Wolves played the entire second half a man down after Jean-Ricner Bellegarde's red card.

Burnley ran Manchester United much closer, but still had nothing to show for a positive performance in their 1-0 defeat.

Son-inspired Spurs show their mettle

Just 12 months ago, Tottenham's hopes of a rare north London derby win at Arsenal crumbled in spineless fashion, but on Sunday Ange Postecoglou's men showed they are made of sterner stuff.

Tottenham, then managed by Antonio Conte, were beaten 3-1 by their bitter rivals at the Emirates Stadium last October after failing to recover having twice fallen behind.

Without a win at Arsenal since 2010, Tottenham once again trailed 1-0 and 2-1 to the Gunners, yet this time they had the character and quality to emerge unscathed.

Son's double extended fourth-placed Tottenham's unbeaten start to six league games and sent a message to their bitter rivals that they are no longer a soft touch.

"We wanted to win so one point is a shame, but the performance was perfect," said Tottenham captain Son.

"I think we showed great character and great bravery and it was very important to come back."

More pain for Pochettino

Chelsea fans thought they had hit rock bottom after finishing 12th last season in a miserable campaign that saw four different managers take the reins at Stamford Bridge.

But the Blues look set for another season to forget despite a summer of huge investment, taking the total spent in three transfer windows under the club's American ownership to over £1 billion.

Mauricio Pochettino has won just one of his first six league games in charge and it was a familiar story for the Argentine as his side failed to find the net for the third consecutive game.

A knee injury to Christopher Nkunku that has meant the French forward is yet to play a minute of competitive action for the club has not helped.

But other big money signings such as Nicolas Jackson, Mykhailo Mudryk and Raheem Sterling are failing to pull their weight in front of goal.

Less than 10 days ago, Pochettino claimed Chelsea will be back in European competition next season "for sure."

That claim is looking more optimistic than realistic with every passing week.

Chelsea sit 14th in the table and face Arsenal, Tottenham, City, Newcastle, Brighton and Manchester United in their next nine games.