Johanna Konta tumbled out of the Miami Open after losing 10 consecutive games in a straight sets defeat to China's Wang Qiang in the second round.
The British number one had seen off American qualifier Jessica Pegula in her opening match and made a decent start against the 18th seeded Qiang on Friday after building a 4-2 lead.
Despite dropping serve, Konta had a break point to move 5-4 ahead but she faltered dramatically thereafter as she was beaten 6-4 6-0 in 84 minutes by Qiang, who will take on Serena Williams next.
There was better luck in the men's draw for Kyle Edmund, seeded 19th, who was given few problems in a 6-3 6-2 victory over Belarusian Ilya Ivashka.
Edmund won 81 per cent of points on his first serve and 65 per cent of points on Ivashka's second serve, breaking his opponent on four occasions.
Edmund next takes on 12th seed Milos Raonic for a place in the fourth round. The Canadian advanced after the withdrawal of Germany's Maximilian Marterer.