Kostyuk, ranked 15th in the world, was the favorite in the special semifinal where the Ukrainian spoke emotionally and with tears in her eyes about the war after her quarterfinal victory over compatriot Elina Svitolina earlier this week.
"We had a difficult night again in Ukraine, especially in Kyiv. So many people dead," she said after the quarter-final win.
She was pitted against Andrejeva, the world number eight from war-torn Russia.
The two met in the final of the Madrid Open a couple of weeks ago and Kostyuk won in two straight sets.
Kostyuk couldn't handle her emotions and made lots of mistakes.
"I was very nervous, she'd had a great season and hadn't lost a match on clay. I'm super happy to get revenge and be in my first Grand Slam final," Andrejeva said in the HBO Max broadcast.
The players did not shake hands after the match.
