It has been a long time since Maria Sharapova had to worry about money, but as well as clocking up a succession of easy wins, she is racking up the cash at an unprecedented rate here at this year's Australian Open.

The world No.2, who won the title here in 2008 and who last year completed a career grand slam by winning the French Open, yesterday reached the quarter-finals by crushing Belgium's Kirsten Flipkens 6-1, 6-0.

In her first four matches the Russian has dropped just five games, the fewest by any woman to this stage in the history of the tournament. Only France's Mary Pierce, at the French Open in 1994, has done better, losing just four games.

In notching those four wins, Sharapova has spent just 249 minutes on court. Reaching the quarter-finals guarantees her $250,000 – her efforts so far rewarded at about $1000 a minute. Nice work if you can get it.

Sharapova has never been the kind of person who likes to hang around the locker-rooms. She is much happier back in her hotel among friends and family – which perhaps explains why she had not heard about the incredible effort Flipkens has made over the past nine months, rising from 262 in the world to the verge of the top 40, even after having blood clots in both calves and her funding stopped by the national federation.

With her use of slice on the backhand and a willingness to come forward, Flipkens gave Sharapova a different look to what she is used to, and in the first couple of games she made a few ragged errors. But once she worked things out, it was one-way traffic and the No.2 seed cruised to another quickfire win.

Sharapova next plays another Russian, Ekaterina Makarova, the woman she beat at the same stage last year. The left-hander is a fine player but, on this kind of form, Sharapova will fancy her chances of going at least one step further.

There are times when things are going so easily that the top players head back out to the practice courts to get a few more miles under their belts. Sharapova has been known to do that in the past but not now, not at the grand old age of 25.

"You also have to pace yourself because it's a two-week event," she said. "Over the course of those two weeks, it's important that your body and mind are as good as they can be towards the end of the second week as they are in the beginning. You're not going to be as fresh. The work that you put in before the tournament is the most important. What you do in the off season, you're not going to put this work in during the tournaments. I actually love coming to tournaments. You practise less and just go and play matches. It's like the best-case scenario."

Considering that she came into this event without playing any warm-up tournaments because of pain in her neck, Sharapova's form has been something of a revelation. But she has made at least the semi-finals in five of the past seven years.

However, with Makarova having beaten fifth seed Angelique Kerber in the previous round, and with Li Na or Agnieszka Radwanska waiting in the semi-finals, Sharapova knows she cannot take anything for granted.

"It's not about waiting to see where you are in the semis or finals, it's about who's ahead of you," she said. "And my next match is against Makarova. I have to do the right things to beat her. If I win that, it's moving on to the next one. That's how I go about a tournament, a grand slam. Obviously, I want to be playing my best tennis towards the end of the second week."

World No.1 Victoria Azarenka and tournament favourite Serena Williams were scheduled to play their fourth-round matches in the early hours. Whoever comes through their half, chances are Sharapova will await.