It's a significant achievement, especially considering her 2009 and 2010 seasons were heavily disrupted by injuries.
Grand slams are a unique beast. You are alongside all the big guns, as the entire ATP and WTA tours come to town. There is huge media interest and all kinds of logistical challenges; even securing time on one of the 20 practice courts here requires some careful planning. And the pressure is higher than at any other time in the season.
Erakovic has become more accustomed to the major environment, since her first grand slam main draw appearances in 2008.
"I'm not that old but I've been playing for a while now," says Erakovic, "Let's go for middle-aged as a tennis player."
She has had some significant achievements in that time; she won a WTA title, reached a couple more finals, cracked the top 40 and beat some players in the top echelon.
What's missing is a famous grand slam run. She has been solid, getting past the first hurdle more than 50 per cent of the time but history will ask for more. Like Kelly Evernden's charge to the last eight in Melbourne in 1987, Cordwell making the semifinals two years later or Steven facing Pete Sampras in an Australian Open quarter final (1993).
It can depend on the luck of the draw - Erakovic has an extremely tough assignment today - but at other times she hasn't risen to the occasion.
"I need to work on [my consistency] a lot more," admits Erakovic.
"As my coach likes to say - every day you go out there is no credit. ... I'm on the right track and hopefully if I keep my head down and keep working hard it will happen."
"I'm playing much tennis than I did last year and I feel I am in a better space," adds Erakovic.
"If I compare things to last year my mental approach is much better."
Erakovic enjoyed a solid training session yesterday, one of the first players on court (8am) before the Melbourne sun was at its worst. Her match with World No24 Muguruza starts at 11am (1pm NZT) today on court seven.
The Spaniard reached the fourth round here last year (defeating Caroline Wozniacki en route) and also made the quarter-finals of the French Open, where one of her victims was Serena Williams.
Kiwis at the grand slams
*Onny Parun 41 (slams), 22 (times beyond first round).
Best effort: Final (Aust Open).
*Russell Simpson 34, 14. Fourth round (Wimbledon).
*Chris Lewis 32, 24. Final (Wimbledon).
*Brett Steven 23, 14. Quarter-final (Aust Open).
*Brian Fairlie 22, 15. Quarter-final (US Open).
*Kelly Evernden 21, 7. Quarter-final (Aust Open).
*Marina Erakovic 20, 11. Third round (Wimbledon, French).
*Belinda Cordwell 13, 7. Semifinal (Aust Open).
*Julie Richardson 8, 3. Third round (US Open).
