Sadio Mane tormented Chelsea as the Liverpool forward struck twice after sparking Andreas Christensen's dismissal in the champions' 2-0 win, while Son Heung-min scored four as Tottenham crushed Southampton 5-2 on Sunday.

Mane was involved in the turning point at Stamford Bridge as the first clash between Premier League title contenders this season swung Liverpool's way.

In first half stoppage-time, Jordan Henderson picked out Mane's run behind Christensen and the Denmark defender responded by rugby-tackling the Senegal star to the ground.

Referee Paul Tierney initially booked Christensen, but VAR told him to consult the pitchside monitor and he changed his decision to a red card. 

Mane grabbed his first goal of the season in the 50th minute as he met Roberto Firmino's cross with a thumping header after eluding Reece James' slack marking.

Mane was gifted his second goal as Chelsea keeper Kepa Arrizabalaga made a hash of trying to play out from the back, allowing the Liverpool forward to intercept and slot into the empty net.

It was the latest costly blunder from Kepa, who was dropped twice by Chelsea manager Frank Lampard last season despite his status as the world's most expensive keeper.

Lampard will be relieved that Chelsea are reportedly close to signing Rennes' Senegal international Edouard Mendy as he looks to replace Kepa.

"It was a clear mistake and Kepa accepted that," Lampard said.

Thiago Alcantara made his Liverpool debut at half-time after his move from Bayern Munich, but the Spain midfielder conceded a 74th-minute penalty with a foul on Timo Werner. Alisson Becker came to Thiago's rescue as he saved Jorginho's spot-kick.

After their chaotic 4-3 win over Leeds on the opening weekend, this was a return to the kind of dominant display Liverpool produced so often en route to their first English title for 30 years last season.

At St Mary's, Jose Mourinho hailed Son and Harry Kane after the pair destroyed Southampton.

Just 24 hours after Tottenham signed Gareth Bale, Son delivered a virtuoso display that showed Mourinho's side already have plenty of firepower.

Bale has returned to Tottenham on a season-long loan from Real Madrid seven years after he left the north London club.

Danny Ings put Southampton ahead in the first half, but Son equalized before the break and scored three more in the second half, with each of his goals coming from Kane assists. 

Kane, who hit the back of the net twice in the first half only to have them ruled out for offside, capped a swaggering display with his second goal of the season.

"Son was on fire and for me Harry Kane was the man of the match, what he did for the team," said Mourinho, whose side had lost their league opener against Everton.

"With him dropping back and connecting the game between the lines for Sonny to attack, the space they created was a problem they couldn't resolve."

Leicester moved to the top of the table on goal difference ahead of Arsenal, Everton, Crystal Palace and Liverpool after they came from behind to beat Burnley 4-2.

After a disappointing end to last season to miss out on Champions League football, Brendan Rodgers' side have responded well with two convincing wins to start the new campaign.

Neal Maupay's quick-fire double inspired Brighton's 3-0 win against Newcastle as the Seagulls claimed their first Premier League victory of the season.

In Spain, Real Madrid began the defense of their Spanish title with a tepid 0-0 draw at Real Sociedad on Sunday as Martin Odegaard made his first league start for the reigning champions against his former club.

Madrid are heading into the La Liga season after making no new signings this summer, with president Florentino Perez admitting the club has to be cautious amid the coronavirus pandemic.

Zinedine Zidane has brushed off suggestions his Real Madrid side could lack freshness this season, with a very familiar XI starting this first game. 

One notable omission was Eden Hazard, whose fitness remains unresolved, even after the summer break. Zidane admitted on Saturday he was unsure whether Hazard has recovered from the ankle injury that required him to have surgery earlier this year.

"It's two points lost but we struggled to make chances, particularly in the second half. We had two or three in the first half," said Zidane.

David Silva made his La Liga return after a decade with Manchester City as he took the place of Isak for the final 25 minutes.

Barcelona do not start their league campaign under new coach Ronald Koeman until next weekend against Villarreal. Granada lead the table with maximum points after two rounds following Sunday's 2-1 victory over Alaves.

In Italy, Andrea Pirlo got his coaching career off to a winning start as Juventus launched their bid for a 10th consecutive league title with a 3-0 win over Sampdoria on Sunday.

Swedish debutant Dejan Kulusevski opened the scoring after 13 minutes in Turin with Leonardo Bonucci adding a second on 78 minutes and Cristiano Ronaldo a late third.

The match was played in front of 1,000 spectators as Serie A stadiums reopened on Sunday to a limited number of fans after a seven-month coronavirus lockdown.

Pirlo could not have hoped for a better start to his coaching career having taken over from Maurizio Sarri this summer.

The win against Sampdoria, coached by veteran Claudio Ranieri, came just days after the former Italy and Juventus star received his coaching diploma.

Juventus next head to Roma next week with the side from the capital held to a goalless draw in their opener on Saturday, before hosting Napoli, 2-0 winners this weekend against Parma.

In France, Kylian Mbappe returned to the starting line-up for Paris Saint-German on Sunday and scored the opener in a 3-0 win at Nice which marks another step on the road to recovery for the French champions.

The 21-year-old, who tested positive for coronavirus on September 7, was on target from the penalty spot in the 38th minute. 

Angel di Maria added a second just before half-time and Marquinhos headed the third after 66 minutes. Mbappe thought he had scored a fourth late on but it was ruled out for offside. He was replaced by Pablo Sarabia shortly after.

"I'm impressed by his performance after only one training session with the team," said coach Thomas Tuchel. 

"He always shows that he can do extraordinary things and that he knows how to make a difference. It helps us a lot."

It was a second successive Ligue 1 win for PSG who began the season still smarting from defeat in the Champions League final. They lost their opening two games and the second ended in a mass brawl against Marseille which led to the suspension of Brazilian forward Neymar.  

Later, Valere Germain salvaged a late point Marseille in a 1-1 draw with Lille thanks to his 85th-minute equalizer. Luiz Araujo had claimed a 47th-minute lead for the visitors at Stade Velodrome.