Justine Henin made a winning start to the defence of her WTA Championship title with a straight-sets victory over Anna Chakvetadze in the round-robin stage.
The world No.1 and top seed in Madrid posted a 6-1 7-6 (7/4) result and improved her head-to-head record to 3-0 against the seventh-seeded Russian.
Henin dominated the opening set, collecting the only two breaks and converting nine of 10 first-serve points.
The Belgian then found herself 2-0 down at the start of the second set, but battled back to regain her serve and force the tie break.
Henin is the overwhelming favourite to win in Madrid and will finish the season as world No.1 for the second successive year after claiming a tour-leading nine titles - including the French and US Opens.
She is also hoping to become the first player to win back-to-back championships at this event since countrywoman Kim Clijsters in 2002 and 2003.
The 25-year-old Henin is playing the round-robin part of this event in the Yellow Group.
Sixth seed Maria Sharapova also made a winning start with a 6-4 7-5 victory over Slovakia's Daniela Hantuchova in the Red Group.
Sharapova, who has endured a frustrating season with injury and won her only title of 2007 in San Diego, has now beaten the eighth-seeded Hantuchova in six of their seven meetings.
In the only other match, number four seed Ana Ivanovic celebrated her 20th birthday by edging out second-seeded Russian Svetlana Kuznetsova 6-1 4-6 7-5 in the Red Group.
The Serbian now has won all three meetings between the two this season, including the Berlin Open final.
Results from the Sony Ericsson Championships, Madrid, Spain:
Yellow Group
1-Justine Henin (Belgium) bt 7-Anna Chakvetadze (Russia) 6-1 7-6 (7-4)
Red Group
4-Ana Ivanovic (Serbia) bt 2-Svetlana Kuznetsova (Russia) 6-1 4-6 7-5
6-Maria Sharapova (Russia) bt 8-Daniela Hantuchova (Slovakia) 6-4 7-5