Petra Marcinko of Croatia enters the Oeiras semi-finals as the higher-ranked player at No. 80, seeking to extend her strong run on clay. The 26-year-old has won three consecutive matches leading into this semi-final, including impressive victories over Greet Minnen and Natalija Brancaccio in straight sets. Marcinko's form stumbled against Tereza Kostovic in her most recent outing, but her overall clay-court performance this week demonstrates the ability to compete at this level. This marks the first career meeting between Marcinko and Kraus, with no head-to-head record between the two players.

Sabine Kraus of Austria arrives at the Oeiras semi-finals ranked No. 120 and will look to upset the favored Marcinko on clay. Kraus has shown mixed results in recent matches, with three wins including a comeback victory over Olga Selekhmeteva, balanced by defeats to Sorana Cirstea and Anna Karolína Schmiedlová. The Austrian player's ability to win from a set down, as demonstrated against Selekhmeteva, could prove valuable in a semi-final setting. Meeting Marcinko for the first time, Kraus has no established head-to-head record and will need to rely on her recent momentum and clay-court adaptability.