Kim Clijsters' 17-match winning streak was ended by Russia's Svetlana Kuznetsova in the semi-finals of the Warsaw WTA claycourt event on Saturday.
Clijsters, who had won consecutive tournament titles at Indian Wells and Miami, lost 2-6, 6-2, 6-3.
Second-seeded Kuznetsova will face another Belgian in the final after Justine Henin-Hardenne withstood a strong challenge from 17-year old Serb Ana Ivanovic to win 6-4, 7-5.
Although Kuznetsova got an early break to lead 2-0, her lack of consistency, especially with her normally reliable forehand, allowed seventh seed Clijsters to sweep the next six games.
But Kuznetsova, who had lost all of her previous three matches to Clijsters, settled down in the second set and her forehand began to do some damage.
She broke to lead 2-0 and held off a break point from Clijsters in the next game by forcing an error with a drop volley before another break gave her the set.
In a high quality contest, Clijsters had plenty of opportunities to hold an advantage in the third set, breaking for 2-1 and earning three points to lead 3-1.
Instead, she netted a backhand to allow Kuznetsova to level at 2-2 and failed to win three game points in her next service game before a fierce backhand winner down the line gave the Russian a 4-2 lead.
BEST TENNIS
As both players continued to fight for each point right to the final ball, Clijsters held off four match points before conceding.
"This is my best tennis this year," said Kuznetsova after reaching her first final of 2005.
"I'm really excited about it because I didn't start the season how I would like. I can't say I played horrible but I couldn't get the results I wanted. I was playing just right but I've worked hard and I'm playing better now.
"Today, I was tense in the first set and in the second set I started to be more relaxed and to play my game and not expect mistakes from her. I started to go for my forehand and just enjoy the tennis. I think we played a great match."
Clijsters was characteristically upbeat despite her defeat.
"This was the first match on clay where I've felt comfortable," she said. "I can take a lot of positive things out of it and although I lost I'm the most satisfied with this match out of the whole week."
Admitting that she took some pace off her serve because her shoulder was still sore, Clijsters said she will seek treatment for it when she moves on to Berlin.
"I served well today but I wasn't serving as hard as in the previous matches," she said. "So that's something I tried to focus on, that I put my first serve in.
TREATMENT
"I'm going to Berlin tonight and I'll have some treatment there. I have to look after it.
"I think it's just because of the clay and the balls are a little heavier here. I'll have to make sure I do all my exercises and build it up a little better. But it should be okay for next week."
Ivanovic, who has jumped into the top 40 after starting the year at 97, made Henin-Hardenne work very hard for her victory in a battle between two unseeded players.
Her heavy forehand kept the Belgian under pressure throughout the one hour 50-minute contest and she threatened to take the contest to a third set as Henin-Hardenne struggled to close out the match.
The Belgian lost a match point at 5-4 in the second set when she netted a forehand, and then threw her racquet to the ground in frustration after netting a smash to drop her serve.
But she broke to lead 6-5 and although Ivanovic saved a second match point, hitting deep to the baseline, a relieved Henin-Hardenne finally closed out the match at her third attempt.
"It was a good fight and maybe I should have won the match earlier but she kept fighting," said Henin-Hardenne.
"I was playing much better in the second set but couldn't finish the points, but I was pleased with the reaction I had, to stay focused and keep fighting. Maybe two years ago I would have lost this second set."
Ivanovic said poor footwork let her down and led to many of her errors.
"I think I didn't move that well today," she said. "I made a lot of mis-hits on both backhand and forehand, and I think I should have got more into the court and put her under pressure.
"But it was a great experience and I think I had my chances in both sets. Unfortunately, I didn't use them but it's something to work on and I'm looking forward to the next match."