British qualifier Harriet Dart lost in straight sets to American Madison Keys in the fourth round at Indian Wells.
Australian Open semi-finalist Keys won 6-1 6-4 against Dart, who is ranked 122 in the world, in California.
Dart, 25, is on course to break into the world's top 100 for the first time following her run to the last 16.
Keys will face Iga Swiatek in the quarter-finals, after the Polish third seed came from a set down to defeat Germany's Angelique Kerber 4-6 6-2 6-3.
Dart missed a break point in the opening game of the contest and that proved to be her only opportunity as 25th seed Keys ran away with the opening set.