Bartoli was on top for nearly the whole match in Miami, but Azarenka had a chance to assert herself when she led 3-1 in the second set.

That was as good as it got for her though and, with her early-season exertions perhaps catching up with her, she surrendered five games in a row, losing 14 of the last 16 points.

It meant Azarenka's winning run was snapped at 26 games, but she told sonyericssonopen.com: "What I've done in the last couple of months, I have to be really proud of myself.

"I could have maybe played better today, that's for sure, but I gave it all I had. But Marion played really well today, and she deserves the win."

Bartoli will now face Polish fifth seed Agnieszka Radwanska in the semi-final.