INDIAN WELLS, CA, USA - Top-ranked Simona Halep says Serena Williams is still the best tennis player in the world.

The World No.1 praised her predecessor after watching her third-round clash at the BNP Paribas Open against sister Venus.

"I think she should have been actually No.1 seed in this tournament because she left as No.1 in the world," said the Romanian. "And to give birth, it's the best thing in the world. It's more than a sport."

Halep took time out to head to the stands and watch the sisters face off for the 29th time in their career.

"It's always nice to watch them," she told reporters. "I love the way that they are motivated and they are still playing at this age, Serena with the kid. So it's a great thing what they do for sport, and it's great that tennis has them.

"It was really fun to come out here and watch the game. And also, you know, I have many things to learn from them. That's why I'm trying just to go in to watch every time I can."

And the 26-year-old, who beat Wang Qiang in the R16 at Indian Wells, added: "I'm the World No.1 in this moment, but I just watched the best player in the world."

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