Nicolas Almagro overcomes Jack Sock challenge

Nicolas Almagro had to defeat American youngster Jack Sock in four sets to progress through to the fourth round of the US Open at Flushing Meadows.

The 11th seed won a tough opening set 7-3 in the tie-break, but Sock, with the home crowd on his side, took the second 7-4 in another tie-break.

Under the intense New York sun, it took a third tie-break to get Almagro back in front, this time with a 7-4 scoreline.

However, it was far simpler for the Spaniard in the fourth as he broke three times to close out the match 6-1.