Tadic set up a club-record four goals in Southampton's 8-0 Sunderland hammering at St Mary's last weekend.
The Serbia playmaker has slotted seamlessly into life on the south coast since his £11million summer switch from FC Twente.
Saints manager Koeman has admitted the 25-year-old has the talent to create more goals than any other Premier League star this term.
And the former Holland full-back believes that if Tadic lays on more goals than the likes of Chelsea's Cesc Fabregas and Manchester City's David Silva then Southampton will challenge for a top-four finish.
"Yes, he has that talent for assists of course," said Koeman of Tadic, ahead of Saturday's home Premier League clash with Stoke.
"Then he plays in a position with a lot of freedom so maybe he can be the player with the most assists, it's possible.
"But compared to Tadic you have some other great players in other teams, so plenty of those could do that too.
"Of course, if you have one player who makes the most assists then it's a big possibility that you are towards the top of the table.
"Dusan has settled in very well, he's a fantastic player and his best quality is his ability to make assists.
"He's a clever player who takes up great positions.
"To win 8-0 isn't normal, but neither is to make four assists in one game.
"The qualities of Dusan are fantastic."
Southampton registered their record Premier League finish of eighth last term, before Mauricio Pochettino departed for Tottenham.
Koeman's summer recruits have the St Mary's club thinking even bigger after a summer of unrest, with the new boss keen on ambition - but also sounding a note of caution.
The former Barcelona defender admitted Southampton could be the league's surprise package, but vowed to review progress "game by game".
"Dreaming is not bad, because always you dream about being the best," said the former Feyenoord boss.
"We are in a good way now, but we know other teams are strong and can bring a good battle to finish in the top six.
"But okay, we will see: game by game, I think that's the best way to reach the highest position in the table.
"Some teams have a tough programme with Champions League, but eight games is certainly not a conclusion.
"It looks like Chelsea and Man City are the strongest, but we'll see.
"Maybe we can (challenge for the top four) because if you believe everything is possible.
"We can be up there, but the difference is that top teams have 24, 25 players already prepared to play Premier League, and teams like Southampton don't have that.
"We have some young players who maybe will get the chance, they are talented players, but they don't have the experience.
"The biggest teams, they have so much more players on that level and that's the difference - but we'll see."
Source : PA
Source: PA