MANCHESTER: Sergio Aguero hit a hat-trick as Manchester City's record-breaking forward inspired a 6-1 demolition of Huddersfield on Sunday.
In the late match Brighton defeated Manchester United 3-2 in the most unlikely result of the day.
Watford defeated Burnley 3-1 in Sunday's other match.
PREMIER LEAGUE
Sunday's results
Brighton & Hove Albion 3-2 Manchester United
Manchester City 6-1 Huddersfield Town
Burnley 1-3 Watford
Saturday's results
Cardiff City 0-0 Newcastle United
Everton 2-1 Southampton
Leicester City 2-0 Wolverhampton Wanderers
Tottenham Hotspur 3-1 Fulham
West Ham United 1-2 AFC Bournemouth
Chelsea 3-2 Arsenal
Jose Mourinho's fears over failing to sign a new centre-back were realised as a shambolic defensive display saw his Manchester United side lose 3-2 at Brighton
For the first time in nearly two years, Mourinho's men conceded more than twice with all three Brighton goals arriving before half-time through Glenn Murray, Shane Duffy and a Pascal Gross penalty.
Romelu Lukaku briefly brought United back into the game at 2-1. But there was little reaction after the break until Paul Pogba's penalty deep into stoppage time as United fell three points behind defending champions Manchester City, Chelsea and Tottenham just two games into the new campaign.
Mourinho warned of a "difficult" season when he wasn't backed in the transfer market before the deadline for Premier League clubs closed before the opening weekend of the season.
Strengthening the heart of his defence was Mourinho's priority and it showed as Victor Lindelof and Eric Bailly endured a torrid afternoon on England's south coast.
In a tempestuous pre-season, Mourinho also clashed with Anthony Martial when the Frenchman failed to return to the club's pre-season tour of the United States after the birth of his second child.
But Martial was recalled to the starting line-up in the absence of the injured Alexis Sanchez and had the first chance when he dashed inside two Brighton defenders before seeing his shot blocked by Duffy.
The story could have been very different for the visitors had Lukaku not wasted a huge chance to open the scoring when he pulled his shot wide of the near post 10 minutes in.
Instead, Brighton went in front when veteran striker Murray caught Lindelof ball watching to flick home Solly March's cross with a classy finish.
Two minutes later, the hosts led 2-0 as Duffy was given the space to control and fire past a helpless David de Gea after United failed to clear a corner.
At Burnley, Watford made it two wins out of two and ended their run of poor away form in impressive fashion as early second half strikes from captain Troy Deeney and Will Hughes gave them a 3-1 win at Burnley in the Premier League on Sunday.
Watford, who have won their opening two games of the season for the first time in the Premier League era, had been winless in their last 12 away games and had not even scored on the road since January.
It took the visitors just three minutes to end that streak as former Burnley forward Andre Gray opened the scoring with a superbly taken volley from a fine Deeney cross from the right flank.
Three minutes later, though, Burnley got back on level terms when James Tarkowski rose well at the back post to head in a Johann Berg Gudmundsson corner.
It was end-to-end, entertaining football for the rest of the first half although there was only one real effort on goal when Deeney tested Burnley keeper Joe Hart with a low, long-range effort five minutes before the interval.
Burnley, who have now gone seven league games without a win, were swept aside by two goals in the opening six minutes of the second half.
The influential Deeney drove home in the 48th minute after being found in the box by a clever pass from Abdoulaye Doucoure then a terrible giveaway by Burnley defender Matt Lowton to Will Hughes resulted in the Watford midfielder firing past Joe Hart with a brilliant left-foot strike.
At Manchester, Pep Guardiola's champions opened their home campaign with a pre-match display of ticker tape and exploding fireworks and Aguero continued the pyrotechnics on the field.
Aguero, who turned 30 in the close-season, has now scored 14 times in his last eight Premier League games at City's Etihad Stadium.
The Argentina star -- City's all-time leading scorer -- joins former Liverpool forward Robbie Fowler on nine Premier League hat-tricks.
Only ex-Newcastle and Blackburn star Alan Shearer has scored more in the competition's history with 11.
City's rampant display underlined why they are such strong favourites to retain their title.
Such is City's strength in depth, Guardiola was able to leave Kyle Walker, Riyad Mahrez and Raheem Sterling on the bench.
And even though City learned this week that playmaker Kevin De Bruyne will be out for up to three months with a knee injury, the fact Guardiola was able to name substitutes which cost his club £230 million ($293 million) in transfer fees, was a sobering thought for their rivals.
After relentless City pressure, which featured Guardiola's team having 80% possession, the champions finally took the lead on 25 minutes, the start of a three-goal blitz inside 10 minutes.
Ederson, Guardiola's ball-playing goalkeeper, struck a magnificent pass over 60 yards, isolating Aguero against defender Christopher Schindler.
The Argentine skilfully held off his marker, twisting and turning before lobbing the ball over keeper Ben Hamer, who had advanced to the edge of his area, from the edge of the area.
Six minutes later, Benjamin Mendy attacked down the left, exchanging passes with Gabriel Jesus, who enjoyed a fortunate ricochet off a defender before drilling the ball home.
And the rout continued when Hamer fumbled a routine Mendy cross and Aguero pounced, tapping in from six yards.