London: Liverpool powered back to the top of the Premier League as Xherdan Shaqiri inspired a 3-1 win over bitter rivals Manchester United, while Arsenal's 22-match unbeaten run was shattered by a shock defeat at Southampton on Sunday.
Jurgen Klopp's side made it six successive league victories thanks to Shaqiri's late double after United's Jesse Lingard had cancelled out Sadio Mane's opener at Anfield.
Shaqiri's superb substitute cameo allowed Liverpool to reopen a one-point lead over second-placed Manchester City after the champions had knocked the Reds off the summit with their win against Everton on Saturday.
Liverpool's first win in their last six meetings with United ended a frustrating streak against the Old Trafford outfit that dated back to March 2016, while also extending their unbeaten start to the league season to 17 matches.
While that was cause for pre-Christmas revelry on the Kop, more significantly, Liverpool's refusal to be subdued by a United team set up by Jose Mourinho with five defenders was another statement of intent as they chase a first English league title since 1990.
"The way the boys played and fought was outstanding. We saw the line up of United, how organised they were and they fight from the back. I'm over the moon about the performance," Klopp said.
"The timing of Shaqiri's introduction was not too bad. We need somebody to score the goals."
Of Liverpool's title bid, Klopp added: "We know we are a good team. We had to prove it and keep on proving it."
Senegal winger Mane put Liverpool ahead in the 24th minute when he broke away from Ashley Young to meet Fabinho's sublime pass with a nimble piece of chest control before shooting past David De Gea.
United equalised against the run of play in the 33rd minute as Liverpool goalkeeper Alisson Becker made a hash of catching Romelu Lukaku's low cross and Lingard finished off the rebound.
Alisson's error didn't prove costly as Switzerland midfielder Shaqiri struck within three minutes of coming off the bench, his shot flicking off the hapless Young into the roof of the net in the 73rd minute.
Shaqiri ensured Liverpool would return to the top in the 80th minute with a stinging strike that clipped the foot of United defender Eric Bailly on its way past De Gea.
United are now 19 points behind Liverpool in sixth place as the pressure mounts on Mourinho following another wretched display.
"We couldn't cope with their fantastic intensity and pressing. They are the strong team, but it's hard to concede two goals in the way we conceded," Mourinho said.
"If you speak about fortunate you speak about their second and third goals."
Meanwhile, Unai Emery admitted Arsenal need to fix their leaky defence after Southampton's Charlie Austin punished a howler from Bernd Leno to stun the Gunners in a 3-2 victory.
Austin settled a thrilling clash at St Mary's when he headed home with just five minutes left after Arsenal goalkeeper Leno misjudged Shane Long's cross.
Southampton had twice taken the lead through Danny Ings, only for Henrikh Mkhitaryan's brace to draw Arsenal level on each occasion.
Leno's mistake handed Arsenal their first defeat in 15 league games and brought a stunning halt to their longest unbeaten run in all competitions since 2007.
Emery's fifth-placed team had not lost since a 3-2 defeat at Chelsea in August and the north Londoners' first setback since the close-season leaves them three points behind the fourth-placed Blues, who won 2-1 at Brighton on Sunday.
Conceding Arsenal need to tighten up at the back, Emery said: "We haven't conceded a lot of chances but today they scored three goals. That is a lot so we need to improve with this.
"We need to do some analysis on how we can improve and do better."
Chelsea put a week of negative headlines for the behaviour of their fans behind them on the field thanks to an inspired Eden Hazard at Brighton.
The Belgian provided his ninth assist of the season for Pedro to open the scoring and then chalked up his ninth goal of the campaign, but first in 13 games for club and country.
Solly March pulled one back with his first goal of the campaign, but Chelsea held on.
"He's very able to come out and play with his team-mates, very able to create spaces. Now, in that position, he has to improve in attacking the box," Sarri said of Hazard's display as the spearhead of Chelsea's attack....