World No.2 Ana Ivanovic suffered a surprise 6-2 7-5 defeat by Elena Dementieva in the semifinals of the German Open on Sunday.
The 20-year-old Serbian, the title holder in Berlin, made far too many unforced errors and was broken five times by the Russian seventh seed.
Dementieva will play compatriot Dinara Safina in Monday's final.
The 13th seed, who has beaten world No.1 Justine Henin and eight-times grand slam winner Serena Williams this week, defeated unseeded Belarussian teenager Victoria Azarenka 6-4 6-1 in the first semifinal.
A runnerup at both the French and U.S. Opens in 2004, Dementieva had won all three previous matches against Ivanovic, but they had never met on clay.
She held her nerve in a tight second set, striking some impressive winners, and shrieked with joy when Ivanovic skewed a backhand wide on the first match point.
"Ana was playing very aggressively and was trying to hit on every single point," Dementieva said.
"I feel like I was more consistent and didn't make lots of unforced errors and that was the key for today's match," she added.
"She's a great player, but I think I was a little bit better today."
Dementieva and Safina have both won two of their previous four meetings, but Safina has been victorious both times on clay.
Ivanovic was playing her second match of the day in the Steffi Graf stadium, having earlier won the deciding set in her quarterfinal against 10th-seeded Hungarian Agnes Szavay.
The pair had to abandon their match late on Friday due to bad light with the score at one set each.
"I was pretty happy with my first set this morning and I felt actually quite good going into the semifinal, but today she was better," Ivanovic said.
"I felt I created a lot of chances in that second set and maybe in the key moments I wasn't as sharp as I should have been."
Safina, the 22-year-old younger sister of former men's number one Marat Safin, faced a stiff challenge from 18-year-old Azarenka in the first set, losing her serve twice.
The Belarussian appeared to be struggling with a knee injury in the second set, which severely hampered her movement and Safina cruised to victory in just under 1-1/2 hours.
Azarenka has had her best run at a tier one event and will break into the top-20 for the first time when the rankings are updated.
Ivanovic needed to reach the final to hold on to her world No.2 ranking and will now be overtaken by Russian former No.1 Maria Sharapova.
