The world number 89, playing in only the second final of her career, produced a nerveless display to claim a 6-2 7-6 (7-4) win over the top seed at the WTA International hard-court event.
Knapp's last final appearance came in Antwerp six years ago when she lost in straight sets to Justine Henin, but she had no such problems on Saturday.
After three holds of serve the first opening came in the fourth game as the Italian broke and then consolidated by saving five break points in the next game.
A further break came Knapp's way in a set where she won 64 per cent of points on her opponent's second serve to move ahead in just 38 minutes.
The Serb improved in the second but still had to come from behind after being broken to trail 4-2.
Jovanovski, who failed in her bid to become the first player to retain her title in Uzbekistan, forced a tie-break but, having won the first two points, she collapsed to concede the next five and could not find a way back.