Sun SentinelReilly Opelka upsets No. 1 seed Jack Sock in second round of Delray Beach OpenSun SentinelIt was only fitting for Reilly Opelka to cap the day at the Delray Beach Open with yet another upset. Opelka knocked off top-seeded Jack Sock 4-6, 7-5, 6-3 Wednesday in the last singles match.