Justine Henin's comeback hit its first speed bump on Friday as Gisela Dulko ousted the former world number one from the second round of the Indian Wells hardcourt tennis tournament.
Henin had made stunning run to the final of the Australian Open in January - in just her second tournament since a return from an 18-month retirement.
But Dulko's 6-2, 1-6, 6-4 victory made Henin one of two Australian Open women's semi-finalists to bow out of this combined WTA and ATP Masters 1000 event, along with China's Li Na.
Li, ranked 10th in the world and seeded seventh, was bundled out by British qualifier Elena Baltacha 7-6 (8/6), 2-6, 7-6 (9/7).
Baltacha, ranked 65th in the world, notched her first victory over a top-10 player - despite falling behind 5-1 in the third-set tiebreaker.
"As the tiebreak started, she just came out with unbelievable stuff," Baltacha said. "I think she hit four backhand winners down the line. And I thought, 'OK, yeah, that's why you're top 10. I understand.'
"But then at 5-1, I went into the zone and I felt really strong and I just fought my heart out," added Baltacha, who saved two match points in that tiebreaker en route to the victory.
Baltacha, who came through two qualifying matches as well as a first-round contest, said she thought the first-round bye given to all 32 seeded players might have made things harder for Li.
"I think sometimes with the top players, the best time to play them is when they haven't played a match and for them it is the first round, because they haven't experienced the conditions, they haven't experienced the court, and it can be a bit tricky for them," she said.
Certainly second-seeded Caroline Wozniacki and 10th-seeded Russian Maria Sharapova struggled mightily to advance.
Sharapova, who had a dozen double-faults, was down a set and trailed 5-3 in the second before emerging with a 4-6, 7-5, 6-2 victory over compatriot Vera Dushevina.
Wozniacki, the 19-year-old Dane who shot to prominence with her runner-up finish at last year's US Open, rallied from 4-1 down in the third set to beat American Vania King 5-7, 6-2, 6-4.
"I just kept fighting for every point," the world number four said. "Vania was playing really, really good. I'm just glad I came through."
Wozniacki said she hoped her first-round tussle would stand her in good stead in her next match, against Maria Kirilenko of Russia.
"For sure I got some points in play today, and I got to run and I got to try a little bit of everything ... Hopefully that can make me stronger for the next round," she said.
Fourth-seeded Russian Elena Dementieva downed Olga Govortsova of Belarus 6-4, 4-6, 6-0, while fifth-seeded Agnieszka Radwanska of Poland had a relatively quick day on court, advancing when Russian Anna Chakvetadze retired with Radwanska leading 6-2, 5-3.
Meanwhile on the men's side, the first-round continued with American James Blake among those advancing.
Blake defeated spain's Dainel Gimeno-Traver 6-3, 6-2 to line up a second-round meeting with 13th-seeded Spaniard David Ferrer.
Taiwan's Lu Yen-Hsun beat Spain's Oscar Hernandez 6-1, 6-2 to line up a clash with seventh-seeded American Andy Roddick.
Roddick played tournaments in San Jose and Memphis last month, but said he was excited to be in a tournament boasting a field headed by world number one Roger Federer and including Novak Djokovic, Rafael Nadal and Andy Murray.
Second-seeded Djokovic and third-seeded Nadal - the 2009 champion - are both scheduled to play their second-round openers on Saturday.
"You know, after Australia we all kind of go and play our own kind of schedule. We have our own agendas," Roddick said. "This ... you kind of get the sense of being at a really, really big event again."