Singapore - Simona Halep has said on Wednesday her lopsided victory over American superstar Serena Williams had given her huge confidence as she eyes a spot in the WTA Finals last four.
The Romanian debutante said she had not even dreamt of such an upset after she won 6-0, 6-2 in Singapore, handing the 18-time Grand Slam-winner her heaviest defeat since 1998.
"No, I didn't," she said, when asked if she had ever imagined such a big victory against Williams, the world number one and two-time defending champion.
"But, you know, I think it wasn't her best day today. She missed a few important balls in the first set.
"But I think the second set was closer. I was very, very focused every point. I just wanted to fight for every point and to be focused for every point."
The French Open finalist also impressed in her opening 6-2, 6-3 win over Eugenie Bouchard at the eight-player season finale, and said she was now confident about reaching the semi-finals on Saturday.
"I can say I have confidence that I can go into the semi-finals. I have a chance now," said the 23-year-old world number four, calling it the best win of her career.
"I just want to think about next round, because will be tough against Ivanovic. First I have to forget this day, because it's really tough to forget it."
Halep's final group game is against Ana Ivanovic. While Williams and Maria Sharapova are the only two players to win the elite event on debut, Halep said Wednesday's victory felt like a breakthrough.
"It's the first time I've beaten Serena. She's number one. It's like a dream to beat one of the (Williams) sisters because they were -- they are -- very good players," she said.
"For my mind it's very important, this victory."