Roger Federer's victory recorded a milestone and Ana Ivanovic's retirement moved Maria Sharapova into the WTA finals on Day 10 at the BNP Paribas Open.
No. 3-seeded Federer swiftly defeated No. 9-seeded Juan Martin Del Potro in just 69 minutes, 6-3, 6-2. His 13 aces propelled the Swiss tennis star to a record 250th ATP World Tour Masters 1000 match victory.
Federer, a former champion of Indian Wells, will face Rafael Nadal, also a former champion of the tournament, in the semifinals.
Ana Ivanovic had made her first semifinal of the 2012 season. The No. 15 seed upset No. 4 Caroline Wozniacki in the fourth round, then upset No. 7 seeded Marion Bartoli in the following round.
But when it came to her semifinal match against No. 2-seeded Maria Sharapova in Friday's semifinal, Ivanovic only made it one set. After a first set that lasted over an hour, Ivanovic retired at 4-6, 0-1.
Official reason for Ana Ivanovic's retirment is a left hip injury. #bnppo12— Ben Rothenberg (@BenRothenberg) March 17, 2012
The No. 2 seed will now face No. 1-seeded Victoria Azarenka in the finals of the WTA bracket.
Men's semifinal matches on Day 11
 Novak Djokovic (SRB) vs  John Isner (USA)
 Roger Federer (SUI) vs  Rafael Nadal (ESP)