Team England's Adam Peaty has booked his place in Monday's 50m breaststroke final, winning the second heat narrowly from Christian Sprenger of Australia with a time of 26.99s.
Peaty qualified with the second fastest time overall and was the only swimmer, along with heat one winner Cameron van der Burgh, to go under 27 seconds.
Scotland's Mark Tully finished second behind the South African in heat one, with Ross Murdoch and Joe Welstead also reaching the final from the second heat.
Wales's Rob Holderness was just edged out as he finished fifth in heat one behind Sandeep Sejwal of India.