The son of Cape Cross defied top-weight and an opening mark of 85 to win in good style under Andrea Atzeni.
Andrea settled Yarroom on the heels of the leaders where he travelled kindly.
He picked up well to take the lead with over a furlong to run and was always doing enough to hold the runner up.
Roger said: "He is a nice, little horse and he has done it well especially as he gave the second over a stone and a half."
At Kempton later in the day, Duroble Man finished third in the mile nursery.