The 40-year-old is still looking for his first victory since taking charge and believes that the reigning Premier League champions will provide a sizeable obstacle to that goal
The 40-year-old, who replaced Nigel Adkins as Saints boss in January, has led his new club to two draws and a defeat in his first three matches.
And he accepts that earning a maiden win on Saturday will be a big ask, with St Mary's hosting the reigning Premier League champions.
Pochettino told the club's official website: "All of our matches are difficult in this division, but we know that Manchester City were the champions last season so we will need to be at our best to beat them.
"For me, Manchester City are a great team with great individual players and they can decide a match on their own."
The Argentine believes his compatriots Carlos Tevez and Sergio Aguero are amongst City's biggest threats, but also highlighted the qualities of David Silva.
He continued: "I can be proud of them because they are Argentinian, and I enjoy seeing them play both at club level and as part of our national team.
"Tevez and Aguero are great players of a great level, almost on the same level as Messi, but Man City also have players like Silva and many others who can dictate the direction of the game."
Rickie Lambert is one short of his 100th strike for Southampton ahead of the game, and Pochettino hailed the Liverpool-born forward.
He said: "Not only for me, but for anybody that likes football they can see that Rickie Lambert is a great footballer.
"Let’s hope that in his next match Rickie will score his 100th goal and then his 101st and 102nd!"
Full-backs Nathaniel Clyne and Luke Shaw both pulled out of international duty this week due to injury, but the former Espanyol boss is hopeful they will prove fit.
He added: "We are working on them and we hope they will be available, but we can’t be sure just yet."