Rennae Stubbs believes there is 'something going on' with Elena Rybakina following her surprise withdrawal from the US Open. The fourth seed handed Jessika Ponchet a walkover just hours before they were due on court at Flushing Meadows.

Rybakina has struggled with injuries and illness this year, pulling out of several tournaments including Indian Wells and the Rome Masters. Earlier this summer, she was forced to withdraw from the Olympics and the Canadian Open due to bronchitis.

She cited another injury as the reason for pulling out of the US Open but Stubbs believes there could have been other factors at play.

She told ESPN: "There’s something obviously going on here. I don’t want to speculate, but this is a very unusual situation. Eight withdrawals this year, undisclosed injury now at US Open. I just think there’s something more going on here.

"This is not a normal situation. I’ve seen her over the last couple of days. She hasn’t looked great. I’ve seen her for years on the tour. I know what she looks like when she’s happy, when she’s healthy, when she’s playing well.

"When she’s playing well, on this surface, she’s one of if not the best player in the world. So what’s going on with her? I think it’s a lot more than we realise.

"This is terrible. It’s sad. She’s such a nice person. She’s so nice to be around all the time. We wish her well and hope she can find whatever she needs to."

Rybakina's withdrawal came just days after she announced that she was no longer working with her former coach Stefano Vukov. The pair initially linked up in 2019 and had a successful partnership, with Rybakina winning Wimbledon two years ago before reaching the final of last year's Australian Open.

There has been some concern over Rybakina following her appearance at a press conference after her first-round win over Destanee Aiava, where she was very guarded over the split with Vukov and refused to give much away.

Asked how it felt to play a match without Vukov, she replied: "Well, of course, it is different. We worked for five years, but still, I got support from Yuri Shchukin, we talked about the tactics and everything, so I was prepared for the match.

"I don’t want to talk about it too much, but yeah, that was our decision to split. I will let you know, guys, if my coach situation is going to change."