TUCSON, Ariz. — Duke freshman phenom Cooper Flagg got his first taste of a true college road atmosphere on Friday night, playing in front of a raucous announced crowd of 14,634 at Arizona’s McKale Center. For a few early moments, he looked a little nervous. It was fleeting. Flagg scored 16 points in the second half, finishing with a game-high 24 as No. 12 Duke pulled away for a 69-55 win over No. 17 Arizona. The preseason All-American shot 10 of 22 from the field, grabbed six rebounds and had three assists, two blocks and a steal…