Parra Santonja took out the No. 2-seeded Cirstea 6-1, 6-4 in a brisk 71 minutes in the semifinals. She faced just one break-point situation in the match and won half of the points when Cirstea served.
She'll face Anastasija Sevastova in Saturday's finals.
Sevastova, who is also playing in her first WTA title match, eliminated seventh-seeded Peng Shuai 6-7 (6-8), 6-1, 6-3 on the strength of eight service breaks.
Saturday's matchup will be the first career meeting between Sevastova, ranked 74th in the world, and Parra Santonja, who is No. 81 this week.
The Estoril Open champion will earn $34,000 with the runner-up taking home $17,500. Cirstea and Peng each collect $9,400 as semifinalists.
Copyright 2010 United Press International.