Nick Kyrgios shares sweet tribute to girlfriend Costeen Hatzi as they celebrate their one-year anniversary

Nick Kyrgios and girlfriend Costeen Hatzi

Nick Kyrgios and his girlfriend Costeen Hatzi celebrate one anniversary

Nick Kyrgios posted a heartwarming tribute to his girlfriend, Costeen Hatzi, to celebrate their first anniversary on Monday.

The tennis star, 27, shared a series of photos to Instagram of the couple and gushed over his girlfriend.

'T H A N K F U L… a year since we met and everything became better,' he captioned the post.

Costeen also shared a sweet tribute to her boyfriend on social media, writing: 'One year with my human. The best year of my life. I love you.'

One year with my human

During an Instagram Q&A, Nick was asked a baby question and replied with a picture of the pair on the beach captioned 'next year' alongside a ring emoji.

Engagement rumours circulated about the lovebirds in May after a Q&A showed Nick hugging the interior designer, 22, with the caption, 'very soon,' alongside heart and ring emojis.

However, Kyrgios' management soon denied the pair were engaged.

Last month, the couple shared videos on Instagram as they set up their Christmas tree and lights.

In several clips, Costeen could casually hang lights on the wall and decorate the tree.