The 25-year-old midfielder set up four of the eight goals that the Saints put past Sunderland last weekend, taking him to seven for the season.
"He has that talent of course and he can be the player with the most assists," Koeman is quoted as saying by the Basingstoke Gazette. "It's possible, but compared to Tadic you have other great players in other teams and they as well can be one of them.
"If you have one top scorer in the team, one player who makes the most assists then it's a big possibility then you are in the top of the table. He's a player who can score goals but his best quality is doing assists and it's a great few in a game and a fantastic player.
"These are players who play in a good position, clever players, and it isn't normal 8-0 but it isn't normal to make four assists in one game. The qualities of Dusan are fantastic."