Zazou will have to be at his best at Hamburg on Sunday if he is to hold off a strong Sheikh Mohammed-led British challenge in the $645,000, Group 1 German Derby. He has won two of the key trials for this 1 1/2-mile test, the 1 1/16-mile, Group 3 Dr. Busch Memorial and the 1 3/8-mile, Group 2 Oppenheim-Union-Rennen, but Zazou, a son of 1 5/16-mile French Derby winner Shamardal, is not a certainty to stay this longer distance.But the acquisition of Olivier Peslier’s services by trainer Mario Hofer might just ensure victory for Zazou who, in between his German victories finished a decent sixth in the French 2000 Guineas over an inadequate mile. Peslier may be the best big-race rider in the world and he has won this race twice, on Borgia in 1997 and Dai Jin in 2003.Monterosso will carry Sheikh Mohammed’s maroon-and-white Darley colors. A Dubawi colt trained by Mark Johnston, he stepped up from the handicap ranks for an impressive score in the 1 1/2-mile, Group 2 King Edward VII Stakes at Royal Ascot. He ran just as well last time when fourth to Cape Blanco in the Irish Derby and will have Kieren Fallon at the controls. Buzzword, trained by Mahmoud Al Zarooni for Godolphin, was 4 1/2 lengths third in the King Edward VII and is winless since taking a six-furlong Group 3 at Longchamp in September.Zazou can expect a challenge from Lindentree, a Waldemar Hickst-trained Dai Jin colt who was 2 lengths second in the Oppenheim-Union-Rennen, but Scalo, who had won the 1 1/4-mile, Group 3 Bavarian Classic for Andreas Wohler, must bounce back form a dull fifth in the Oppenheim-Union-Rennen.