Jack Sock came from two sets down to beat Marin Cilic and John Isner had a straight sets win over Borna Coric to give the United States a 2-0 lead after the opening day of their Davis Cup quarter-final against Croatia in Portland, Oregon.

The United States and Croatia faced off in their Davis Cup quarter-final in Portland on Friday (15th July).

Jack Sock took on former US Open winner Marin Cilic in the opening match.

Cilic took the first two sets, however, Sock suddenly burst into life and fought back to level the match at two sets all.

With the momentum behind him Sock triumphed in the fifth and final set to secure the 4-6, 3-6, 6-3, 6-4, 6-4 win.

John Isner's match with Borna Coric was a much more straight forward affair.

The big serving Isner typically secured victory with an ace, as he eased to a 6-4, 6-4, 6-3 win over Coric.

So the US hold a 2-0 lead heading into Saturday's play.