Belinda Bencic has revealed she found out about being drawn against Serena Williams in the first round of the Australian Open through her Twitter page 'blowing up'.

Bencic has dropped to 48 in the WTA rankings following an injury-plagued 2016 season.

And the 19-year-old, who reached a career-high seventh in February, has been handed the toughest of assignments with a first-round contest against Williams.

The American is aiming to break Steffi Graf's record for the most grand slam singles titles in the Open era by registering a 23rd major success.

But Bencic came from a set down to beat Williams in their last meeting at the Rogers Cup in 2015, and the Swiss is relishing a match that she was informed of via social media.

"My Twitter was blowing up. I was like, 'what's going on?' That's when I saw it," Bencic said of the draw.

"My first reaction was actually [that I was] really happy. So I think I'm super pumped [and] excited I get to play on the big court, I guess.

"Everyone is like, 'Oh, bad luck with the draw'. Me, I'm … pretty happy and excited about it.

"We're going to play on the big court. It's a big match, playing against Serena Williams. It's what everyone's working for. To play Australian Open, of course like first round, but that's how it is. I'm just pumped about it.

"I still remember … the last game [against Serena], every point, everything. It was, for sure, my biggest win until now.

"I hope I can take this memory and put it to positive energy to be, [be] super confident on the court, and play good."

Bencic was forced to retire from her match with Yulia Putintseva at the Sydney International because of a toe injury, but believes she is close to full fitness.

"Last year was very tough. I got one injury, then it was a circle into the next one. I just didn't stop. I was really happy about it. I came back, didn't play very good," she added.

"Now I think I'm really motivated to play, first of all. I'm so happy to be here.

"Physically I have nothing that bothers me, except this thing in Sydney. No, I think I'm pretty close to 100 per cent."

Asked if she can recall her successful gameplan from the Rogers Cup clash with Williams, Bencic replied: "Yeah, for sure I remember. I'm going to try to do that again. I'm not going to tell you now what exactly because then she will know."