Costeen Hatzi, 25, has been seen at an end-of-summer party in Sydney following rumours she has split from her tennis boyfriend Nick Kyrgios. Picture: Supplied

Rumours the pair have parted ways emerged after they both removed each others initials from their Instagram bios. Picture: Instagram

Pictures of Kyrgios, 29, have been largely wiped out from her Instagram page. Picture: Instagram

Hatzi has dated the tennis bad boy since 2021 and was regularly seen supporting him courtside during their relationship. Picture: James Morgan/Getty Images

The model has reportedly been taking public swipes at Kyrgios on social media in recent days. Source: Instagram

Kyrgios has a party boy reputation with this being cited by some as the reason for the unconfirmed split. Picture: Supplied

While neither have confirmed a break-up, Hatzi was just seen attending an Aperol party in Sydney solo. Picture: Supplied

She posed for a number of photos at the event, held at The Beach Club in Nielsen Park. Picture: Supplied

Guests were invited to celebrate the end of daylight savings and raise a glass to the cooler seasons ahead. Picture: Supplied

Arianna Sunshine was also at the bash. Picture: Supplied

As were Arora Atkinson and Sarah Maloney. Picture: Supplied

Brianna Walton looked stylish in jeans and a white tee. Picture: Supplied

Guests all sipped on the famous Italian beverage. Picture: Supplied

And enjoyed a set by DJ duo All Rise, Harvey Robbins and Calum Mann. Picture: Supplied

The tennis WAG looked stunning. Picture: Supplied