City's win moved them back into third place but Guardiola said that third is the best they can hope for, because Chelsea and Tottenham Hotspur have the top two places secured.
"If you want to win the Premier League or be there until the end you have to be strong at home and not drop points at home against Southampton and Middlesbrough". He is a true leader in the back for Southampton, while always making smart decisions in the team's build-up play. This season, they're incredible.
The Southampton defence has had a look of steel in recent weeks, while the City attack is as potent as they come in the English top flight.
The next stumbling block has been a source of pain for the fans in the past, too.
Southampton resides in an unimpressive ninth place with five teams close behind. The club's second leg of their 1-0 aggregate loss to Real Madrid was just three days later and, at that point, the Spanish side weren't leading the tie. Guardiola claims he has not yet decided who will play in goal at Southampton on Saturday, saying he will make up his mind on the day of the game.
First he escaped his marker at the far post but could only volley Gael Clichy's cross wide.
That afternoon was notable for a delightful no-look pass from Martin Demichelis that set up the left-back's goal.
While both teams have been good in their respective strong departments, things haven't been quite the same at the opposite end of the field. I don't think Saints' chances of success are as unlikely as the bookies reckon so it's worth a small stake to get with the hosts at St Mary's.
WATFORD, ENGLAND - MARCH 04: Manolo Gabbiadini of Southampton shoots during the Premier League match between Watford and Southampton at Vicarage Road on March 4, 2017 in Watford, England.
Manchester City should come out the winners of this match.
Aguero found himself playing back-up to Jesus upon the youngster's January arrival from Palmeiras as Guardiola felt the Brazil worldwide offered more to City's overall play.
Back-to-back wins and just the one defeat in six has lifted the Saints into the top half of the table, meaning that a fourth successive top-10 finish could well be achieved - no mean feat when focus was elsewhere during a key period of the season.
Nobody celebrates a goal quite like Vincent Kompany.
Two became three soon afterwards when De Bruyne looped in a cross from the right and Aguero thumped home a header.
Since then, the former Atletico Madrid man has scored ten goals in his last ten matches and Guardiola believes he has helped alter his game to become a more complete player.