Katie Boulter fell agonisingly short of a stunning win over five-time Grand Slam champion Iga Swiatek as Great Britain’s hopes of reaching the United Cup semi-finals were ended by Poland.

Boulter, 28, needed victory to send the best-of-three tie into a deciding doubles, but lost 6-7 (4-7) 6-1 6-4 against world number two Swiatek in Sydney.

Both players shared a warm embrace at the net after an enthralling contest which lasted almost three hours.

“I’m exhausted. I’m happy I won so I didn’t have to play the doubles,” said Swiatek.

“This match was so crazy, there were so many changes of momentum.”

Britain’s hopes relied on Boulter causing a shock against the five-time major champion after Billy Harris narrowly lost to former world number six Hubert Hurkacz.

Harris, 29, pushed 16th-ranked Hurkacz in the opening match of the best-of-three tie before going down 7-6 (7-3) 7-5.

Poland, who were one of the pre-tournament favourites, will face Kazakhstan in the last four on Friday.