Kyle Edmund has failed to progress into the second round of the Australian Open after cramp hindered his efforts against Damir Dhumzur.
The British number three blitzed his way through the opening set but the scorching Melbourne heat eventually took its toll on the 21-year-old.
Edmund fought hard to open up a two-sets-to-one advantage, but he was visibly suffering during the closing stages and eventually succumbed to a 1-6 7-6 4-6 6-3 6-1 defeat.
Fellow British representatives Andy Murray, Aljaz Bedene, Dan Evans and Johanna Konta will all have to contend with similar conditions on Tuesday, with each of their matches being scheduled for the afternoon in Melbourne.
