Dubai, United Arab Emirates (SportsNetwork.com) - World No. 1 superstar Serena Williams was a stunning semifinal loser, while her older sister and two-time tournament champion Venus was an upset winner Friday at the $2 million Dubai Tennis Championships.

Capable unseeded Frenchwoman Alize Cornet stunned the reigning U.S. and French Open titlist Serena in 6-4, 6-4 fashion in 1 hour, 22 minutes. Serena staved off four match points before succumbing to the 26th-ranked Cornet, who beat Serena for the first time in four career tries.

Cornet broke the mighty Serena three times, while getting broken only once in the big upset.

After opening her season with a title in Brisbane and seven straight match wins, Serena has gone 2-2, including a fourth-round loss against former No. 1 Ana Ivanovic at the Australian Open.

Meanwhile, the 2009 and 2010 Dubai titlist Venus waltzed past eighth-seeded fellow former world No. 1 and 2011 Dubai champ Caroline Wozniacki 6-3, 6-2 on the hardcourts at Dubai Tennis Stadium.

"I feel like I've just gotten so much better since my first round to now, just feeling comfortable on the court, feeling comfortable when I'm behind, feeling comfortable when I'm in the lead," the wild card Venus said. "So it reminds me a lot when I first came on tour, having to learn a lot, so I feel like I'm learning lessons all over again."

Venus is a perfect 5-0 lifetime against Wozniacki and has never dropped a set against the Danish star.

The 33-year-old world No. 44 Venus is seeking the 45th title of her career and her first one since prevailing in a small event in Luxembourg in 2012. She was a runner-up in Auckland last month.

The 24-year-old Cornet will appear in her seventh career WTA final, and her first one on a hardcourt, seeking a fourth title. Her last championship came in Strasbourg in her native France last season.

Venus and Cornet will clash in Saturday's final, with the American leading their lifetime series, 3-0. Venus bested Cornet in the round of 16 in Dubai back in 2009.

Cornet will try to become the eighth woman to defeat both Williams sisters at the same tournament.