Valencia stood tall in Istanbul and rallied past Fenerbahce (86-90), handing the Turks their fourth straight loss in the EuroLeague.
The Spaniards came back from a 10-point deficit at halftime (43-33) and outscored their opponents 43-57 to cruise to the victory.
Van Rossom scored eight of his 20 points in crunch time for the winners, while Klemen Prepelic went for 13 points in the fourth quarter.
Six players scored in double figures for the losing squad, with Dyshawn Pierre having a team-high 18 points.
Valencia improved to 6-3, whereas Fenerbahce dropped to 4-7.