Ronald Koeman's side were tipped to be fighting relegation from the Premier League this season following a mass exodus of their first-team players.
However, the Saints have started the campaign well having secured a draw and two victories following their opening-day 2-1 defeat to Liverpool.
"They play fantastic football and have threats all over the pitch," Monk said in this afternoon's press conference. "The new players that have come in have scored goals and their mentality is the same as last season.
"It will be a very difficult game, and we're under no illusions as to how tough it will be on Saturday."
Swansea have lost just once in four league games so far this season.