By Anton Lagani, Lawn Tennis Correspondent, Posted: Wednesday, October 8, 2008 10:24pm PST USA

SHANGHAI/DOHA--(lawntennismag.com) The ATP Tour and the WTA Tour both begin in January of each year and both wind down towards championships in November as each crowns its tour champion for the year. The WTA Tour will host its Sony Ericssson Championships at Doha, Qatar the week of November 3rd. The ATP Tour hosts the Tennis Masters Cup Shangahi the next week, November 17th, at Shanghai, China. Both tournaments will follow a round robin format after the top 8 players of each tour qualify from points obtained from tournament play throughout the year. Serena Williams and Rafael Nadal

World number two Roger Federer of Switzerland won the ATP Tour's year end title in 2003, 2004, 2006 and 2007. In active tour players, world number two Roger Federer of Switzerland is a four time year end Tennis Masters Cup champion. Federer won the title in 2003, 2004, 2006 and 2007. David Nalbandian of Argentina took the title in 2005. World number two and US Open champion Serena Williams of the USA is one of only three active players to have ever won the WTA Tour's year end tournament. Williams posted a victory in 2001 while fellow American Lindsay Davenport won in 1999. Australian Open champion Maria Sharapova of Russia won the WTA Tour's year end tournament in 2004 but will miss this year's tournament with a shoulder injury. Davenport, currently ranked 34th, will not finish near the top eight. More shake ups at the top of women's tennis this decade besides Davenport's rankings drop include the sudden departure of former world number one Justine Henin of Belgium. Henin took the year end title the last two years but retired from tennis earlier this year even while being ranked number one. Amelie Mauresmo of France won in 2005 but has fallen to 25th in the rankings this year. A second Belgian, Kim Clijsters, won twice, in 2002 and 2003 before also announcing her retirement from tennis last year in May citing injuries. Share on Facebook: