The Thurloe Thoroughbreds-owned colt won at Sandown a fortnight ago and made it back-to-back successes with a game win under James Doyle.
James soon adopted a good position on the heels of the leaders. American Artist travelled strongly and was well-positioned to strike when the runners turned for home.
He picked up well to hit the front and stayed on under a strong drive by James to repel all challengers by a length.
Roger said: "American Artist has thrived in recent weeks and is a colt on the up. He didn't look entirely at ease on the tight turns and we may look at a more coventional track in the future."
American Artist, a son of Danehill Dancer