Britain's Fran Jones has been helped off court in a wheelchair after collapsing during a match in Colombia.
The 24-year-old was attempting to serve in the ninth game of a deciding third set in Bogota when she fell to the floor.
Jones, the British number five, was unable to finish the Colsanitas Cup first-round match.
"Due to a physical issue, Francesca Jones has withdrawn from her match against Julia Riera at 6-2 5-7 5-3 in favour of the Argentinian," read a Colsanitas Cup statement.
"We wish the British tennis player a speedy recovery.