Williams targets fresh start
Serena Williams and Victoria Azarenka will look to make it two wins from two matches at the WTA Championships in Istanbul on Wednesday.
The pair both won their round-robin clashes in straight sets on the opening day of play at the Sinan Erdem Dome, but in contrasting fashions.
Williams began her defence of the Billie Jean King Trophy with a crushing 6-3 6-1 win over Angelique Kerber while second seed Azarenka, her most likely challenger, struggled past Sara Errani.
The first set of Azarenka's 7-6 (7/4) 6-2 victory lasted an hour and 28 minutes - 24 minutes longer than Williams' entire match.
Italian Errani led 5-2 and served for the first set three times but each time Azarenka broke back before taking it on the tie-break.
The 24-year-old admitted to rustiness having lost her only two matches since being beaten by Williams in the final of the US Open more than a month ago.
On Wednesday, she takes on seventh seed Jelena Jankovic, who is back among the world's top eight for the first time in three years.
In the red group, Williams meets third seed Agnieszka Radwanska, whose hopes of reaching the semi-finals were badly hit by a 6-4 6-4 defeat against Petra Kvitova in the final match on Tuesday.
Kvitova is a big danger indoors and won the title the first year the tournament was held in Turkey in 2011.
At that stage she was close to being world number one and looked set to be a multiple grand slam winner, but inconsistency has been her great weakness.
After losing in the third round of the US Open she briefly dropped out of the top 10 but she hit form in Asia, winning the title in Tokyo, and was hugely impressive in beating Radwanska.
The Pole has lost all seven of her previous meetings against Williams, with her only set coming in last year's Wimbledon final.
"I think against her I will have nothing to lose so I'm just going to go on court and try," said Radwanska.
"I think pretty much sometimes it all depends on her. When she really starts to play her best tennis, it's really very hard to do anything."
The first match of the day sees fourth seed Li Na begin her campaign against Errani in the white group.
The Italian was hampered by pain in her right calf against Azarenka and admitted there was no guarantee she would take to the court on Wednesday.
She said: "I hope to recover. We are trying with the physio to do everything that's good to make it better, but you never know. Tomorrow I will try and I will see."
Errani has a busy schedule having also qualified for the doubles in Turkey with Roberta Vinci, while Italy take on Russia in the Fed Cup final next weekend.