Geovanni joined the club on a free transfer from Manchester City in the summer.
“The signing of Geovanni has been an absolute result for us and to have a player like him at Hull City is fantastic for the club” Duffen told the Hull Daily Mail.
“The results he has been able to create since he has been at the club have been fabulous.
“We are determined to make sure he stays with us.
“He is one of those players that you think can score whenever he picks the ball up and turns towards goal.
“I thought something may happen when he got the ball at the Emirates and again on Sunday against Spurs.
“The goalkeeper just watched it fly in to the net to his right because there was nothing he could do about it.”