Stefanos Tsitsipas withstood a tough test from 2012 U.S. Open champion Andy Murray, emerging with a 2–6, 7–6 (7), 3–6, 6–3, 6–4 victory after nearly five hours. The No. 3 seed from Greece is among the group of young challengers to top-ranked Novak Djokovic, but had to fight just to get past the opening day….