Serena Williams has expressed her delight at beating Ana Ivanovic in her opening match of the WTA Finals.

The defending champion was in dominant form on Monday, earning a 6-4 6-4 victory over the Serbian in Singapore.

"I'm really excited with how I played tonight," Williams is quoted as saying by the WTA's official website. "To see all my fans over there was really exciting - thank you so much!

"I've been working hard and am glad to be here. Today I was really fighting all the way. Ana played so well, I was just trying to fight as hard as i could. I was even losing my voice from shouting 'come on' so much!"

Monday's other match in the red group saw Simona Halep defeat Eugenie Bouchard in straight sets.