ISTANBUL, Turkey - The WTA Championships features each season's top performers, many of whom were that year's Grand Slam stars. And this year, for just the second time in the 41 years the season finale has been held, all four of the Grand Slam finals were also match-ups at the WTA Championships.

Victoria Azarenka defeated Maria Sharapova in the Australian Open final, but was beaten by the Russian in the semifinals in Istanbul. In the other three cases, the same player was victorious in each contest. Sharapova topped Sara Errani in the Roland Garros final and in round robin action at the season finale. Serena Williams bested Agnieszka Radwanska in the Wimbledon final and in the final four at the WTA Championships. Finally, Williams was a winner over Azarenka in the US Open final and in round robin play in Istanbul.

The only other year in which each of the Grand Slam finals were also played at the WTA Championships was in 1984, when the season finale was staged in February and preceded the majors, with its participants based on results from the previous 12 months. Chris Evert routed Helena Sukova in the WTA Championships quarterfinals, and Martina Navratilova defeated Evert in the final. The Grand Slam finals that followed mimicked those results, with Navratilova upending Evert at the French Open, Wimbledon and US Open, and Evert edging Sukova at the Australian Open.

There have also been replays of three of the Grand Slam finals at the season finale twice - in 1989 and 2006. Here is a list of all of the years in which there was at least one:

1974: 1
1975: 2 (WTA Championships played in April)
1979: 1 (WTA Championships played in March)
1983: 1 (WTA Championships played in March)
1984: 4 (WTA Championships played in February)
1985: 1 (WTA Championships played in March)
1986: 1 (WTA Championships played in March)
1989: 3
1990: 1
1991: 1
1997: 1
1998: 1
2004: 2
2005: 1
2006: 3
2007: 1
2008: 1
2009: 1
2010: 2
2012: 4