"Happy New Year everyone! I have a feeling it's going to be a great year!! My first victory of 2014 #shesaidyes!!," golfer McIlroy, who rang in the New Year with Wozniacki in Sydney, wrote.
The two former world number ones in their respective sports have been dating for more than two years and erroneous reports their relationship was over last year was proposed by some as an explanation for McIlroy's drop in form.
Wozniacki, 23, pulled out of this week's Brisbane International with an injured right shoulder but is confident she will be able to play in this week's Sydney International in preparation for the Jan. 13-26 Australian Open.
"Happy New Year everyone! Rory and I started 2014 with a bang! ... I said YES!!!!" Wozniacki tweeted above a picture of her hand sporting an engagement ring.