The oft-uttered rhetoric is that the Saturday lunchtime kick-off offers the opportunity to heap pressure on rivals with a win.
As the title race temperature rises from a simmer to the boil, the City boss stated that Chelsea, Liverpool and Arsenal all have the same demand - to win every game regardless of results elsewhere.
Ominously for their rivals, City have won 16 of their last 20 games, losing just one match in that remarkable run.
“The four teams have the same pressure until the end of the season – they all want to win the title,” Manuel argued. “Everyone knows that they must win – whether they know our result or not.
“We just depend on ourselves until the end of the season – it’s important to continue playing the way we did in the second half because I thought it was a great performance.
“We are enjoying a very good second round of fixtures where the results are much better than the first half.
“We’ve had four wins and one draw in our last five games – maybe we had low performances in the month of February and at the start of March but I think that now the team has come back to its best performances.”
A “game of two halves” is one of football’s most well-worn clichés.
There is no better way to describe this latest match, according to the Chilean, who believes there was too much space between his defence, midfield and attack in a first-half which saw the visitors dominate possession.
However, the City boss was pleased with the quality of defending and the way in which his team took control of the match after the break.
“That was a very different game, in the first half and in the second,” he asserted.
“In the first 45 minutes we didn’t play well because there was a great difference between our lines so we didn’t recover the ball against a team playing very well.
“But in our worst moment, we scored three goals and I don’t remember any clear chances for Southampton in the first half.
“I think that we made an important mistake not to have a small space between the lines, you must do that if you want intense pressing.
“Southampton always had time to turn and create danger in our box. We didn’t recover the ball well but we defended very well. Even though they had a lot of the ball they didn’t create chances.
“It was 3-1 at the break which wasn’t the difference between the teams but we played much better in the second half, we recovered the ball well and made a lot of good chances against a very good team.”
One of the major talking points at half-time was City’s second goal.
Pellegrini rubbished claims that this decision was pivotal to the destination of three points and emphasised that City deserved their win.
“I don’t think that the second goal changed the game because we scored a few minutes later,” he said.
“I don’t think the difference was just the second goal, we won 4-1.
“If we had only won the game 1-0 maybe you can say it was an important mistake by the referee.”
Pellegrini’s Southampton counterpart Mauricio Pochettino was disappointed with the officiating from Chris Foy and his assistants.
The Argentine boss believes that the penalty awarded to City in the second minute was harsh and he was distraught that the linesman didn’t spot David Silva in an offside position in the build-up to the home side’s second goal.
“The first 45 minutes, we were superior to a team equipped to win the Premier League,” Pochettino declared.
“To beat a team like City, a team full of world class players, you have to have a perfect day and have the refereeing decisions to be fair and they weren’t today.
“I’ve just seen it [the penalty decision] on TV and I don’t think you can give that after two minutes and their second goal was clearly, two metres, offside.
“That’s the kind of game you play at school and when you get a bad call like that it can affect any player and it did today – it affected our players.”