Russia's Alexandrova shines in Seoul to win third career title
The two battled to a lengthy tiebreaker after an evenly matched hour-long first set in front of more than 10,000 spectators, a record for the Seoul event.
But everything changed in the second set as Russia's second-seeded Alexandrova (27) dominated the former French Open champion from Latvia, who required a medical timeout at 3-0 down for a foot problem.
"I think it was tough for me to start because I was really nervous and I couldn't find the rhythm in the first couple of games," said Alexandrova.
"But the longer we played, the better I felt on the court.
"I think maybe somewhere in the end of the first set I finally found the rhythm and I just continued to keep it that way in the second set."
The Russian is enjoying the best season of her career, having also won the Libema Open in the Netherlands in June, and is set to rise to a career-high 21 in the world.
"You always want to achieve more," Alexandrova added.
"I want to go higher and maybe end the year top 20 in the best-case scenario."
Ostapenko (25) had advanced to the Korea Open final after former US Open winner Emma Raducanu retired in the third set of their semi-final with injury.
