West Brom have conceded 22 goals in the last five top-flight home games, the most since Aston Villa in 1935.
Ilkay Gundogan continued his inspired run in front of goal with two excellent strikes, Joao Cancelo scored while an offside flag was raised and several players seemed to stop, and Riyad Mahrez powered in a fourth before the break.
Boss Pep Guardiola says he's showing why he's one of the best midfielders in the world.
Mahrez turned provider after the interval, with his low ball across the face of the penalty area tapped in from close range by Raheem Sterling in the 57th minute.
Stuart Armstrong opened the scoring for Southampton in the third minute, but Mikel Arteta's side hit back with goals from Nicolas Pepe after eight minutes, Bukayo Saka six minutes before the break and Alexandre Lacazette, who sealed the win 20 minutes from time to continue his side's recovery in the league.
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This story was produced with the financial assistance of the Facebook and Canadian Press News Fellowship. Blumberg also stated that the COVID-19 vaccine is not a shot in the dark.
Meanwhile, it is now 11 matches in all competitions without a win for Steve Bruce's 16th-placed Newcastle after they were beaten 2-1 at home by Leeds.
City continued to enjoy virtually unparalleled possession for the remainder of the game, but were unable to add to their tally, and speaking afterwards, Pep Guardiola was delighted with his side's concentration and determination which took his team a point ahead of Manchester United.
"This league is demanding and cruel at times", Bruce said. "It's the only way I know to be a manager - just think about Sheffield".
In a Premier League season of wild unpredictability, City are beginning to look ominously in the sort of groove that helped them claim back-to-back titles before Liverpool knocked them off their perch last season.
"The way we play, everyone is involved in the attack and the play and creating chances and trying to score - it doesn't matter, it is important to arrive in the box and create chances", added the Spaniard, who was not surprised at Gundogan making the most of a more advanced role.