Indian Wells: Heather Watson loses to Monica Niculescu
British number two Heather Watson lost the last six games as her six-match winning run came to an end against Monica Niculescu in Indian Wells.
Watson, who won her third WTA title in Monterrey last week, won seven games in a row to lead 2-0 in the third set before Niculescu prevailed 6-4 2-6 6-2.
British men's number two Aljaz Bedene earlier lost 7-5 2-6 6-3 to Russia's Mikhail Youzhny in the opening round.
Andy Murray and Johanna Konta will begin their campaigns on Saturday.
Both Britain's top players are seeded and have byes in round one at the BNP Paribas Open, with second seed Murray taking on Spain's Marcel Granollers and 25th seed Konta facing American Madison Brengle.
Murray, playing with fellow Scot Colin Fleming, lost in the doubles on Friday, beaten 7-5 6-7 10-8 by John Isner and Milos Raonic.
Venus makes 'fairytale' return
Venus Williams returned to Indian Wells after a 15-year boycott but was beaten 6-4 6-3 by Japanese qualifier Kurumi Nara.
The American, 35, had been booed and whistled, along with her father Richard and sister Serena, in 2001 after Venus withdrew from her semi-final against Serena.
Richard Williams had alleged that racist comments were directed at them and the sisters refused to play at Indian Wells until Serena ended her boycott last year.
Elder sister Venus followed suit on Friday and received a hearty reception from the main stadium crowd of about 7,000 spectators.
"It was enough of a fairytale to come here and play," she said after the defeat. "A win would have been nice, but that means I have to come back, play next year."
Serena Williams, the world number one, later beat Laura Siegemund of Germany 6-2 6-1, and there were also wins for third seed Agnieszka Radwanska, fifth seed Simona Halep and eighth seed Petra Kvitova.