An evening on the verge of the irrational. And a world No. 1 and defending champion Daniil Medvedev tossed around by a Nick Kyrgios alternating brilliant inspirations and absurd decisions. The front side, the best of the Australian, ended up taking the upper hand to tame the Russian in four sets (7-6 [11], 3-6, 6-3, 6-2), Sunday in the round of 16 of the US Open. He will meet Russian Karen Khachanov in the quarter-finals.