The latest chapter in Southampton's remarkable season was written on Sunday when Tadic scored a historic winner against Manchester United.
The 1-0 victory - Saints' first at Old Trafford since 1988 - moved the south-coast club above United into third in the Barclays Premier League.
Few predicted Southampton would be in such a lofty position after losing a host of star players last summer, but Tadic insists the squad firmly believes a top-four finish is within the club's grasp.
"Yes, the season is long, but we have a great belief," Tadic said when asked whether Saints are good enough to end the season in the top four.
"We have beaten Arsenal and Manchester United and they are direct opponents for what we want to achieve
That's really important
"We just need to believe in our skills and to see what is good and what is not good, and to keep going."
Tadic was one of 10 signings new manager Ronald Koeman made in the summer to offset the impact of losing the likes of Luke Shaw, Adam Lallana and Dejan Lovren.
The 26-year-old Serbian, who cost Southampton Â£10million, was part of the Saints team that lost to United last month even though their opponents only managed two shots on target.
Tadic felt it was fitting, therefore, that Saints won on Sunday despite having just one shot on target themselves.
"Last time we played really well and deserved to win, but we didn't get three points," the midfielder said.
"Now we did get three points even though maybe we don't deserve to."
Despite scoring the winner, Tadic was criticised by Koeman for removing his shirt in his goal celebration - an act that earned him a booking.
Tadic himself admits he has no idea why he celebrated like he did.
"You never think about the celebration
I don't know why I do that, but it doesn't matter," the former FC Twente man said.
"It's important that we are all happy."
Source : PA