Serena Williams believes withdrawals won't take the shine away from this year's US Open and subsequently a record equalling 24th Grand Slam triumph.

Williams' chances have been boosted with six of the top ten deciding against playing at Flushing Meadows but she believes it has increased standing due to not having any fans and the mental challenges that come with it.

"It still has to be tennis that's played, asterisks or not," she told reporters on Friday.

"I think this whole year deserves an asterisk, because it's such a special year - history we have never been through in this world.

"I think we are living a future history lesson. I think regardless, there is always going to be some asterisk by it, because it's never been done before.

"If you win, it was, like, wow, I was able to win in this crazy circumstance where there was no fans. It was just so sterile and weird, but I mentally came through. It might be a more mental test than anything."

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