ISTANBUL, Turkey - In two weeks, Sara Errani will become just the fifth player since the institution of the round robin format at the TEB BNP Paribas WTA Championships in 2003 to compete in singles and doubles. That is quite a feat for any player, much less one who had never previously finished in the Top 25 in the singles race and whose highest doubles race finish was eighth.

"I'm so proud to be able to represent my country at the WTA Championships in both singles and doubles," Errani said. "This has been a wonderful year for me, and to be able to play not only singles in Istanbul, but also doubles with my good friend Roberta Vinci, is a great way to finish the season."

Errani, who collected four WTA singles and eight doubles titles this season, is currently seventh in the singles race and first in doubles alongside Vinci. Here is how the players to participate in singles and doubles since 2003 stood in the race entering the TEB BNP Paribas WTA Championships:

Here is how those participants ended up doing in singles and doubles at the TEB BNP Paribas WTA Championships:

Notes: Prior to the switch to the round robin format, three players won both the singles and doubles at the WTA Championships in the same year. Martina Navratilova did it five times, Jana Novotna once and Martina Hingis once.