Third seed Elena Dementieva wore down Jelena Jankovic 6-3, 4-6, 6-4 to win the Los Angeles Open.
The 21-year-old Jankovic stood strong in backcourt rallies until the third set, when she took a medical timeout at 3-0 down for heat sickness.
After falling behind 5-0, Jankovic fought back gamely to 5-4, but Dementieva finally shut her down when she broke the Serbian in the final game and won the two-and-a-half hour match with a forehand crosscourt winner.
Dementieva, who won her second title of the season, is projected to rise to number five in the world rankings.