The son of Elusive City had shown promise in maidens on the all-weather but benefitted for the switch to turf.
He was always to the fore under Andrea Atzeni, tracking the pace set by the favourite, Order of Service.
Under pressure up the straight, Kohlaan showed his inexperience but ran on strongly to win by a length.
Roger said: "This horse is improving with racing but he is still green and immature. Hopefully he won't go up much in the handicap and can step up on this."
Kohlaan on Warren Hill Grass this spring