Joao Cancelo:
With Kyle Walker potentially ruled out for City until after the World Cup, Guardiola is lucky to have such a versatile full-back to rely on.
Cancelo can play on either flank without any drop off in quality defensively, although he's almost more threatening on the left-hand side.
The Portuguese is the master of an outside of the foot pass and sent one glorious deep cross onto the path of Riyad Mahrez, who volleyed just over the bar.
His response was to do it all by himself, twisting James Ward-Prowse inside out before smashing a left-foot shot into the bottom corner.
Kevin De Bruyne:
The Belgian took another notable step up the ladder towards being one of the all-time Premier League greats.
De Bruyne broke City's career assist record and moved up to fifth on the all-time Premier League assists list when he set up Phil Foden's second goal.
He now has nine so far in the Premier League already has he closes in on his own single-season record of 20 shared with Thierry Henry. With Haaland as a team-mate and De Bruyne getting even better, it wouldn't be a surprise if that record is smashed this term.
Haaland's goalscoring team-mates:
Of course, Erling Haaland was eventually on the scoresheet but by then the game was long over.
What will have delighted Pep Guardiola is that City were ahead emphatically long before he was on the scoresheet.
Haaland played his part by dragging Southampton's centre-halves out of position to create the space for his team-mates, who proved they too can finish their chances.
Phil Foden:
Switched flanks to the left-hand side from the Manchester derby, but it had little impact on his performance.
It might not have been another hat-trick but it was another game when he was crucial in the final third.
Foden created the chance for Cancelo to drive at Southampton for the opener with a quick pass that saw him flattened by Kyle Walker-Peters.
After missing a one-on-one with Bazunu, he was presented with a second opportunity less than a minute later and made no mistake with a deft finish.