DELRAY BEACH, Fla. (AP) Jack Sock won the last seven points of a second-set tiebreaker to beat Donald Young 6-4, 7-6 (2) on Saturday in an all-American semifinal at the Delray Beach Open.
Sock, seeded third and ranked 21st in the world, will face No. 1 seed Milos Raonic of Canada or No. 7 Juan Martin del Potro of Argentina on Sunday in the final. Raonic and del Potro played Saturday night.
Sock never lost his serve all day and allowed Young only one break-point opportunity. Young took a 2-0 lead in the second-set tiebreaker, but didn't win another point.
Sock hasn't dropped a set and has gone 3-0 in tiebreakers through his first four matches.
This marked the second straight week that the 69th-ranked Young reached a semifinal before falling to another American. Young lost a Memphis Open semifinal to eventual champion Ryan Harrison.