Caroline Wozniacki became the world number one after defeating Petra Kvitova in the third round of the China Open in Beijing.
Serena Williams has relinquished her grip on the world number status but could return to the top of the summit as soon as next week when she takes part in the Generali Ladies Linz tournament.
Meanwhile Wozniacki will be concentrating on her quarter-final match with Ana Ivanovic after the Serb beat Elena Dementieva in the third round.
Ivanovic is enjoying a resurgence of form recently and Wozniacki will need to be weary of the former world number one, despite her 2/5 favouritism to beat Ivanovic.
The two have met twice before during the 2008 season when Ivanovic beat Wozniacki by two sets to love in both the French Open and the Australian Open.
Ivanovic is a decent price at 7/4 to beat Wozniacki and 4/1 to beat Wozniacki in straight sets.
However Wozniacki has made the final in three of her last four tournaments, missing out on a fourth in the US Open when she lost to Vera Zvonareva in the semi-final – Wozniacki is 13/5 to win 2-1.
Home favourite and this year’s Australian open semi-finalist Li Na, faces a quarter-final with Anastasija Sevastova and the partisan crowd will be hopeful that Na progresses.
Na is the 1/5 favourite to win the match but her form on the hard courts is pretty poor compared to her opponent.
Sevastova may have been handed a walkover by Nadia Petrova in the third round, but she beat Dominika Cibulkova and Sam Stosur in the earlier rounds and is a big price at 10/3 to beat Na.
All of Sveastova’s matches in the China Open have gone the distance and she is 13/2 to win in three sets.
Wozniacki is the 6/4 favourite to win the China Open. See the full China Open betting odds market here.