Melbourne, January 27: Serena Williams says she is "so proud" of her long-time friend Caroline Wozniacki after the Dane succeeded her to become the Australian Open champion. Williams, who has not played a competitive match since capturing the title at Melbourne Park exactly a year ago, was too on edge to watch.

"I got too nervous to watch but woke up to @CaroWozniackinew number one and Aussie open champ," she tweeted soon after the27-year-old beat Simona Halep 7-6 (7/2), 3-6, 6-4, becomethe new world number one in the process.

"So awesome. So happy. Are those tears? Yup they are," Williams added, with Wozniacki sobbing after ending a longwait to win a Grand Slam title. "From a year ago to today, I'm so proud my friend, soproud. Literally can't even sleep now," added the 23-timeGrand Slam winner.

Williams was pregnant when she won the Australian Open last January. She gave birth to a girl, Alexis Olympia, last September and married father Alexis Ohanian in November.

She is set to make her return next month at a Fed Cup tie when the United States play host to the Netherlands on an indoor hardcourt at Asheville, North Carolina. Wozniacki also won praise from Rod Laver -- with the court on which she won named after the Australian legend.

"Congratulations @CaroWozniacki - welcome to the Club," he tweeted. Pam Shriver said on Twitter that it was "abreathtaking final" while Boris Becker stated that "bothplayers deserve all the credit in the world".