Garbine Muguruza made an imposing start to the WTA Finals by confidently swotting aside Czech Lucie Safarova 6-3, 7-6 (4) in their White Group opener on Monday.
American Stephens stayed calm and saw off an increasingly agitated Angelique Kerber in the winner-takes-all night match to complete round-robin play with a spotless 3-0 record after she wrapped up a 6-3, 6-3 victory against the German.
Top seed Simona Halep was pooled with grand slam winners Maria Sharapova and Flavia Pennetta in a formidable looking Red Group for the end-of-season WTA Finals on Friday.
Caroline Wozniacki overcame a mid-match wobble and withstood a barrage of big hitting to get her WTA Finals title defence back on track with a 7-5, 3-6, 6-2 victory over Petra Kvitova at the Singapore Indoor Stadium.
World No 1 Serena Williams was handed the best possible draw for her WTA Finals title defence with the 33-year-old American grouped with two injury doubts and avoiding the in-form players.
China's Li Na made it a hat-trick of White Group victories, overpowering back-injury victim Victoria Azarenka 6-2, 6-1 on Friday to march through to the semi-finals of the WTA Championship.
Poland's Agnieszka Radwanska stayed patient in the face of a barrage of big serving to advance to the last four of the WTA Finals for the third time in a row with a 7-5, 6-3 victory over Karolina Pliskova on Friday.
Jelena Ostapenko enjoyed a winning end to her season with a 6-3, 6-1 triumph over Karolina Pliskova in her final White Group match at the WTA Finals on Thursday and vowed to return as a better player after her first taste of the event.
A calm Sloane Stephens picked her shots to perfection to overcome Japan's Naomi Osaka in a battle between the last two US Open champions at the WTA Finals on Monday before top seed Angelique Kerber was upset by Kiki Bertens.
Elena Dementieva lost 6-4, 6-2 to Italy's Francesca Schiavone at the WTA Championships on Friday before stunning the crowd by announcing her retirement from tennis.
Russia's Svetlana Kuznetsova raced to a 6-2, 6-1 victory over Australian Daria Gavrilova to defend her Kremlin Cup title in Moscow on Saturday and secure a place at the season-ending WTA Finals.
Earlier in the day, Karolina Pliskova became the first woman to advance when the big-hitting Czech curbed her attacking instincts to beat compatriot Petra Kvitova 6-3, 6-4 and record her second win against a single loss in White Group play.
Venus Williams secured her place in the semi-finals of the WTA Championships when she completed her round-robin matches with a comprehensive 5-7, 6-1, 6-0 win over her sister Serena on Thursday. It was the first time Serena had lost a set 6-0 since the 2007 Miami final, after which she recovered to defeat Justine Henin for the title.
Venus Williams won her second match in two days at the season-ending WTA Championships on Wednesday when she beat Elena Dementieva 6-4, 4-6, 6-3 to leave herself on the brink of the semis with one round-robin match to play. Russian Vera Zvonareva also remained undefeated after a 6-3, 6-7, 6-4 victory over Serbia's Ana Ivanovic in the white group.
The class act which Obama has put up signifies a new 21st century America. In the past, most Democratic Party nominees hailed from a chic, upper class, White liberal background. Franklin Roosevelt and John F Kennedy had family wealth written over them. Jimmy Carter and Bill Clinton were professionals who had made a lot of money before they got the ticket. That is why Obama's defeat at the hands of Hillary Clinton was considered natural by political pundits.
Halep became the first Romanian to reach the summit of the women's rankings when she beat French Open champion Jelena Ostapenko in the semi-finals of the China Open in Beijing, a feat she feels is the high point of her career to date.
Caroline Wozniacki put a huge dent in Maria Sharapova's bid to finish the season as world number one by overcoming some distracting bright lights to down the Russian 7-6(4), 6-7(5), 6-2 in their marathon opening group match of the WTA Finals on Tuesday.
Caroline Wozniacki 0-6, 6-3, 7-5 and advance to the last four at WTA Finals on Friday, the Frenchwoman topping the Red Group after top seed Simona Halep lost later in the day.
Venus Williams gained revenge for her Wimbledon final defeat by Garbine Muguruza when the American advanced to the last four of the WTA Finals with a gutsy 7-5 6-4 victory over the Spanish world number two on Thursday.
Spain's Garbine Muguruza moved to the brink of the WTA Finals last four with a 6-4, 6-4 win over Angelique Kerber on Wednesday after Petra Kvitova opened her account with a 7-5, 7-5 victory over fellow Czech Lucie Safarova.
Serena Williams clinched the year-end World No 1 ranking for the fourth time without hitting a ball on Friday after Maria Sharapova, the only woman with any chance of overtaking her, was eliminated from the WTA Finals.
Venus Williams produced a vintage display full of guts and determination to grind out a 7-5, 6-7(3), 7-5 victory over Jelena Ostapenko at the WTA Finals on Tuesday to set up a White Group decider for a semi-finals berth against Garbine Muguruza.
Dominika Cibulkova kept her hopes of reaching the last four of the WTA Finals alive with a gritty 6-3, 7-6(5) Red Group victory over Simona Halep at the Singapore Indoor Stadium on Thursday.
World No 1 Serena Williams showed her determination to defend her WTA Championships title by sweeping to a 6-3, 6-1 win over Angelique Kerber at the season-ending event on Tuesday.
Svetlana Kuznetsova dug deep into her reserves to overcome Agnieszka Radwanska 7-5, 1-6, 7-5 in their WTA Finals round robin opener on Monday, the late-arriving Russian upsetting the defending champion in a thrilling encounter.
Angelique Kerber was forced to dig deep in her WTA Finals opener before the German world number one battled past Dominika Cibulkova 7-6(5), 2-6, 6-3 in a high-class baseline slugfest at the Singapore Indoor Stadium on Sunday.
A summary of sportspersons in the news on Sunday.
Round-robin formats at tennis tournaments can cause confusion but Serena Williams has an easy solution, just keep winning.
Romania's Simona Halep kicked off her campaign for a maiden WTA Finals title in emphatic fashion with a thumping 6-0, 6-3 victory over US Open champion Flavia Pennetta in the opening match of the eight-woman season-ending tournament on Sunday.
Maria Sharapova is renowned for her sheer determination in the face of adversity but in Singapore on Saturday, the Russian was quick to cast doubt over her chances of winning the WTA Finals after an injury-ravaged second half of the season.
World No 1 Serena Williams beat Agnieszka Radwanska for the eighth time in eight matches to move ominously towards the semi-finals of the WTA Championships on Wednesday.
Garbine Muguruza continued her dream debut at the WTA Finals by completing round robin play with a perfect 3-0 record to advance to the semi-finals after a hard fought 6-4, 4-6, 7-5 victory over Petra Kvitova on Friday.
Maria Sharapova is used to having to rebuild from scratch after suffering a string of debilitating injuries throughout her career, but the Russian is still surprised at how well she is playing in her latest comeback at the WTA Finals.