Sharapova remains a towering figure in women's tennis, figuratively speaking, and in Davis' case literally.

Davis is short. No not really short so much as really quite small. She is 157 centimetres tall or five foot 1½ inches. She is the second shortest woman at the open, a mere pair of Havaianas taller than Japan's Karumi Nara (154cm).

Davis won on Wednesday when Slovakian Magdalena Rybarikova (180cm) retired after losing the first set. On Monday, in the first round, she also upstaged 26th ranked Russian Anastasia Pavlyuchenkova – a mere poppet at 177cms.

Everyone Davis plays is taller than her, so this is not uncommon, but Sharapova is something else,

Sharapova makes pole vaulters look stocky. Even the word willowy is too cumbersome. She is 188cms tall, or six foot 1½ inches – an exact foot taller than Davis. In tennis, for reach and power size matters.

Davis playing Sharapova is literally like putting Cyril on Max Gawn. Actually Cyril would still beat Gawn. It's like playing Brent Harvey on Tom Hawkins or Caleb Daniel on Will Minson. OK, with a net in between.

"I was in the locker room and [Sharapova] was just like towering over me. I never realised how tall she was. I never played Maria before so I am really excited," Davis said.

"I think everyone I play against is taller than me; I am one of the shortest on the tour. I think my speed and my tenacity make up for the size. I think I serve pretty well for my height."

Women's tennis is a game dominated by the tall and the muscular with a sprinkling of wee ones – like (recently retired) Justine Henin and Simona Halep. But even Halep and Henin have 10cms on Davis.

Playing Sharapova she will be on centre court. Surprisingly for a 22-year-old ranked 103 in the world, it will not be her first moment on the big stage. She played her first ever professional match there in 2011 when she was smashed by Sam Stosur.

Now, as then, she will seek to use her pace and aggressive tenacity to create the upset. Her pace might be tested with Sharapova latterly discovering a drop shot.

"It's something that I have added to my game, and that's helped me, you know, especially playing against opponents that stay far back," Sharapova said.

"It's actually something that I had to add, because I was getting really frustrated losing to my hitting partner all the time.

"He just stood so far back behind the baseline I was like, I just can't handle him beating me so often. I have to just change things around. That's kind of when I started getting into that a little bit. He was a little surprised. But it started working, so that was good."

Davis is the daughter of a cardiologist and a nurse from America's south and a devout Christian. She is confident and excited playing Sharapova, but said divine intervention would not be unwelcome.