Dementieva had a losing record to Serena, and she never won a major, but her best effort was eliminating Capriati from the 2004 USO semifinal. At least she served a good purpose there.
And her best effort was winning Olympic Gold beating Serena Williams along the way. Seriously, do your research.
Dementieva came back from a set, 2-4 down to take the next 9 games. Incredible resilience.