Jack Sock was down two sets to love , but in the third set he brought his game to a completely different level taking the third set , then fourth .
Jack Sock finally clinching the fifth set to take the US team to a 1 - 0 lead .
Jack Sock was down two sets to love , but in the third set he brought his game to a completely different level taking the third set , then fourth , and finally clinching the fifth set to take the US team to a 1 - 0 lead .