After yet another scare, Sergio Aguero masterminded a spectacular Manchester City comeback with five goals against Newcastle on Saturday.

City's 6-1 thrashing of Newcastle provided a reminder of the team's title credentials after back-to-back Premier League losses and a Champions League setback.

Aleksandar Mitrovic headed Newcastle in front in the 18th minute and it took Aguerountil three minutes before half time to equalize.

But in a fizzing 13-minute spell at the start of the second half, Aguero added another four goals, while Kevin de Bruyne also got in on the scoring act for the leaders.

Aguero had only scored three goals in the first two months of the season before Saturday and his tally might be have greater had he not been taken off with around 25 minutes remaining.

"In other games he was maybe having a lot of chances but not scoring," City manager Manuel Pellegrini told the BBC. "But today he returned to his normal amount of chances he creates but this time he scored.

"He was not upset about going off. He was having treatment at half time and it was a risk for him to finish the whole game."

Without a win after eight games, Newcastle sunk to the bottom of the standings. Northeast rival Sunderland moved ahead on goal difference with a 2-2 draw against West Ham. Sunderland threw away a 2-0 lead to leave Dick Advocaat still searching for his first victory over the campaign.

It's similarly bleak for Aston Villa, which is a point further ahead with just one win to its name so far. Marko Arnautovic gave Stoke a 1-0 victory at Villa Park.

There were victories for two of the surprise packages of the early season: Crystal Palace and Leicester.

Leicester quickly bounced back from its first loss of the season last weekend by winning 2-1 at Norwich. Jamie Vardy scored a seventh goal in eight league games for Leicester.

Yohan Cabaye set up Yannick Bolasie's header and then scored from the penalty spot as Palace beat West Bromwich Albion 2-0 to move ahead of Leicester into third place on goal difference.

A meeting between promoted clubs Bournemouth and Watford ended in a 1-1 stalemate.

Chelsea's troubled season took another turn for the worse on Saturday when Southampton inflicted a fourth loss in eight games of Jose Mourinho's Premier League title defense.

Southampton seized on defensive frailties to win 3-1 at Stamford Bridge, leavingChelsea 10 points behind fledgling leader Manchester City and only four points above the relegation zone.

The result made Mourinho himself raise the prospect of Chelsea firing him - just as owner Roman Abramovich did in 2007 after three years of the Portuguese in charge. However, he said he would not walk away from the challenge of turning things around.

"If the club wants to sack me, they have to sack me because I'm not running away," he said. "If the club sacks me they sack the best manager that this club has had."

Mourinho was brought back in 2013 and he delivered the title by eight points in May.

But the team has rarely looked like champions this season, not even at Stamford Bridge. Two of Chelsea's losses have come at home, where Mourinho had only been beaten once in the league before this season across his two spells as manager.

Willian gave the hosts a 10th-minute lead by curling in a free kick, but Steven Davis leveled before halftime. Sadio Mane and Graziano Pelle sealed Southampton's win after the break.

Chelsea was booed off as Southampton won at Stamford Bridge for the first time in almost 14 years.

Captain John Terry was restored but Saints exposed the now familiar failings in the defense, which just five months ago formed the foundation for winning the title.

Chelsea has conceded at least two goals in seven of their eight Premier League games this season and time and again Sadio Mane, Graziano Pelle and Dusan Tadic found holes in the Chelsea defense.

Willian scored a fourth free-kick goal in four games to open the scoring, but Chelseaafterward scarcely tested goalkeeper Maarten Stekelenburg.

Southampton equalized after Ramires was booked for a foul on Mane, and Jose Fonte played the ball long to Pelle, with his back to goal.

Pelle held off defender Gary Cahill, chested it and, one bounce later, Davis hit it sweetly to score.

Mourinho was incensed when Radamel Falcao was booked for diving in the area after a collision with Stekelenburg, and Southampton went ahead shortly afterward when Cahill lost the ball and Terry failed to intercept Pelle's pass to Mane, who sneaked in behind to slot into the net on the hour.

Mane ran at Chelsea and then played in Pelle for the third goal in the 72nd.

While Southampton also had a clear penalty appeal in the first half when Branislav Ivanovic pulled down Virgil van Dijk by his shirt, Mourinho blasted referee Robert Madley over the Falcao incident.

"The penalty is a giant penalty, and he was afraid to give (it)," Mourinho said. "The referees are afraid to give decisions for Chelsea. Why? Because when they give, there is always a question mark from you (the media). ... We are always punished."