They're all International title winners, they've all been to the semifinals or better at Grand Slams this year, and they're all going to Sofia in two weeks. Who are they?
WTA Staff

SOFIA, Bulgaria - Ekaterina Makarova, Dominika Cibulkova and Andrea Petkovic have been announced as the first three qualifiers for the Garanti Koza WTA Tournament Of Champions, the $750,000 year-end event set to take place at the Arena Armeets from October 28 to November 2.

This event, the season-ending championships of the WTA's International Series, brings together six players who have won at least one International-level title during the year - as well as two wildcards - who aren't taking part in singles at the BNP Paribas WTA Finals Singapore presented by SC Global.

And the first three qualifiers are now official: Makarova, who won her International-level title at Pattaya City; Cibulkova, who won hers at Acapulco; and Petkovic, who won hers at Bad Gastein.

All three players will be playing the tournament for the first time in their career.

Makarova has had her best season to date this year, highlighted not only by the aforementioned Pattaya City title, but also by some spectacular performances at the Grand Slams - most notably her first Grand Slam semifinal at the US Open. She had never been ranked higher than No.19 in the world coming into this year and has shattered that, just this week setting her new career-high of No.13.

Cibulkova has also had her best season to date this year, her best period being the first four months of the year that saw her reach her first Grand Slam final at the Australian Open, win that title in Acapulco and break into the Top 10 for the first time (setting a new career-high of No.10 in the world).

And Petkovic has put together one of the great comeback seasons in recent memory, bouncing back from an injury-plagued last few years to work her way back into the Top 20 on the heels of reaching her first Grand Slam semifinal at Roland Garros and capturing the Bad Gastein title during the summer.

The previous five winners at the Tournament Of Champions are Aravane Rezai (2009 in Bali), Ana Ivanovic (2010 and 2011 in Bali), Nadia Petrova (2012 in Sofia) and Simona Halep (2013 in Sofia).