Heather Watson advanced to her first quarter-final in more than a year after a marathon three-set win over Na-Lae Han at the Thailand Open.

The British number six will climb back into the world’s top 150 after a 6-3 5-7 6-4 victory that took her two hours and 33 minutes to achieve. Watson led by a set, and a double break before her South Korean opponent found her range and hit back to force a decider.

A break ahead in the final set, Watson hurled her racket in frustration after being pinned back to 4-4. But she regained her composure to break once more and then finished the job with a superb drop shot on her second match point.