KATIE BOULTER came close to claiming the biggest scalp of her career today as Iga Swiatek edged a three-set thriller to knock Great Britain out of the United Cup.

Swiatek, the world number two, prevailed 6-7 (4) 6-1 6-4 in an epic contest just short of three hours to steer Poland into the semi-finals in Sydney.

The turning point came in the third set with Boulter leading 2-1 and a break up, with Swiatek heading to the physio room for a medical time-out and appearing to be in some discomfort.