Haaland shook off any signs of rust by opening the scoring for the visitors in the final minute of the first half, meeting Kevin De Bruyne’s cross with a powerful close-range header that gave Southampton keeper Gavin Bazunu no chance.
Jack Grealish made it 2-0 in the 58th minute, sprinting onto another sublime pass from De Bruyne before firing a left-foot shot that Bazunu saved, only for the winger to slam home the rebound with his right to double City’s advantage.
Grealish turned provider 10 minutes later, racing away down the left before chipping a cross to Haaland, which the Norwegian acrobatically volleyed home for his 30th league goal of the season.
He was replaced by Julian Alvarez and though Southampton pulled a goal back through substitute Sekou Mara in the 72nd minute, they conceded a penalty almost immediately and Alvarez restored City’s three-goal lead from the spot.
