MIAMI (AFP) - Eugenie Bouchard's poor run of form continued as the Canadian suffered a first-round exit at the hands of Australia's Ashleigh Barty at the Miami Open on Wednesday.

Wild-card Barty's 6-4, 5-7, 6-3 win set up an all-Australian clash in the second round against 14th seed Samantha Stosur.

But for the 23-year-old Bouchard, a former world No. 5 who has slumped to 56th in the world rankings, it was another blow after her first-round exit in Indian Wells.

"It's been a bit of a struggle," said a stone-faced Bouchard, who was unable to account for her loss of form.

She was a beaten finalist at Wimbledon in 2014 but, apart from a run to the semi-final at Sydney, where she was beaten by Britain's Johanna Konta, she has been unable to make an impact this year.

Barty reproduced the gutsy tennis that helped her secure her maiden WTA title at the Malaysian Open in Kuala Lumpur last month.

"We've had a good pre-season and get a good foundation and the stars aligned a bit for us this year so far. We have worked hard and it is just that hard work starting to pay off," said the 20-year-old Australian.

Serbia's Jelena Jankovic was another high-profile early exit, the 2008 Miami finalist falling 4-6, 6-4, 7-6 (7-3) to Kazakhstan's Yaroslava Shvedova.

Britain's Heather Watson, who reached the fourth round in Miami last year, was beaten 7-6 (7-4), 6-1 by Romanian qualifier Patricia Maria Tig.