Two-time champion Andy Murray suffered a straight-set loss to Dusan Lajovic in the first round at the Miami Open.
Former world number one Murray, winner in both 2009 and 2013, was beaten 6-4 7-5 by the 76th-ranked Serb.
It comes a week after the fatigued 35-year-old Scot lost to Jack Draper in the third round at Indian Wells.
Fellow Briton Kyle Edmund is also out after losing 7-5 7-5 to Wu Yibing, while Emma Raducanu was defeated in the women's draw by Bianca Andreescu.
Murray, currently 52nd in the world, won a remarkable seven deciding sets among several marathon victories in an exhausting opening to his 2023 season.