Johanna Konta has overcome the challenge of Zheng Saisai to progress through to the semi-finals of the Bank of the West Classic.

The British number one is looking to defend the ranking points that she accumulated on the North American swing last summer, and she moved closer to retaining her place in the top 20 by the end of the US Open with a 6-2 4-6 6-3 win over the world number 74.

Konta started on top and two breaks of serve were enough to take the opening set, and it appeared that she would ease to victory after striking again at the start of the second.

However, Zheng found a rich vein of form to level the contest, and she matched Konta during the first four games of the decider as she threatened to record a second win over the 25-year-old in the space of six weeks.

Konta managed to get back on track, however, and a total of three breaks of serve in the third set ensured that she set up a last-four showdown with Dominika Cibulkova.