Venus Williams has described her victory over Samantha Stosur in the quarter-finals of the Cincinnati Open as a "huge achievement" following her health problems.
The American, who suffers from the autoimmune disease Sjogren's Syndrome, saw off the US Open champion and third seed in three sets to seal her place in the semi-finals.
"For me and everything in my life, this is a huge achievement," she said after the match.
Williams will now play either top seed Agnieszka Radwanska or ninth seed Li Na for a spot in the final.
