Tomas Berdych has progressed into the third round of the Shanghai Masters after beating Jack Sock by a 7-6 4-6 6-4 scoreline.
The Czech player needed almost two-and-a-half hours to see off the American, who is currently 28 places below him in the rankings.
There was little to separate the two players in the opening set. Berdych looked to have gained an advantage when he broke in the third game, but Sock responded with a break of his own to level matters. The set went the way of serve after that as it headed into a tie-break, which Berdych won 7-3.
The second set followed a similar pattern to the first, with both players dominating on serve aside from one early break each. However, it was Sock who would claim it in the 10th, breaking the Berdych serve for a second time to take the set into a decider.
A number of unforced errors from Sock midway through the deciding set allowed Berdych to break to love and, after a hold of serve, the world number five moved two games ahead.
He did not relinquish that advantage and, despite Sock saving two match points in the final game, the Czech was able to book his place in the next round.