DOHA, Qatar, Nov. 4 (UPI) -- World No. 1 Jelena Jankovic and Venus Williams highlighted Tuesday's round-robin winners at the $4.55 million Sony Ericsson Championships in Qatar.
The top-seeded Jankovic beat fourth-seeded fellow Serb Ana Ivanovic 6-3, 6-4 on Day 1.
Jankovic, the U.S. Open runner-up, moved to 1-0 in the four-player White Group. Ivanovic is the reigning French Open champ and was runner-up at the Australian Open back in January.
The former world No. 1 Ivanovic will return to action Wednesday with a match against eighth-seeded Russian Vera Zvonareva.
The seventh-seeded Williams, upset second-seeded Russian Dinara Safina 7-5, 6-3. Safina was this year's runner-up at the French Open and Olympic Games. Williams, the reigning two-time Wimbledon champion, will return to the court Wednesday against Olympic gold medalist Elena Dementieva, who is seeded fifth this week.
Safina next plays third-seeded Serena Williams.
Also Tuesday, Zvonareva beat sixth-seeded fellow Russian Svetlana Kuznetsova 6-2, 6-3. Kuznetsova is a former U.S. Open champion and former U.S. and French Open runner-up.