The Red Devils made a statement by putting nine past the Saints at Old Trafford on Tuesday but Guardiola has warned the Citizens not to think about other teams amid the title race.
Manchester City comfortably saw off Burnley at Turf Moor with a 2-0 win to go top of the Premier League table despite having a game in hand.
First half goals from Gabriel Jesus and Raheem Sterling made sure the Citizens leave Lancashire with the three maximum points. City have now won their last thirteen games in all competitions.
Speaking to the media after the game, the Spanish coach was asked whether Manchester United's 9-0 win over Southampton put pressure on them.
Guardiola said: "We have to do our job. It's a big mistake to think about other sides. When we were 12th we were thinking forget about the Premier League title, if we can achieve being in Europa League next season. It's not about runs of games, statistics. It's always about the next game, next game."
The former Barcelona and Bayern Munich coach then reflected on his side’s win against the Clarets: "We struggled a little bit to break - the first pass, first movement. The first 15 minutes of the second half was our best football. Unfortunately, we could not score a third or fourth goal.
"In the last 15 minutes we passed the ball without the intent to attack, just to control.
"Strikers need goals for their confidence. Gabriel Jesus played really good."
