Former world number one Serena Williams has sent her congratulatory message to her friend, Caroline Wozniacki, after the Dane won her first Grand Slam title.

The second seed saw off top seed Halep 7-6 3-6 6-4 to win her first major title in her 3rd final appearance.

The 27-year old is now expected to regain the world no.1 in Monday’s rankings.

Serena Williams took to her official Twitter handle to congratulate Wozniacki. She tweeted: “I got too nervous to watch but woke up to @CaroWozniacki new number one and aussie open champ. So awesome. So happy. Are those tears? Yup they are. ? from a year ago to today I’m so proud my friend so proud. Literally can’t even sleep now.”

I got too nervous to watch but woke up to @CaroWozniacki new number one and aussie open champ. So awesome. So happy. Are those tears? Yup they are. 😭 from a year ago to today I'm so proud my friend so proud. Literally can't even sleep now

— Serena Williams (@serenawilliams) January 27, 2018