When the Australian Open draw came out, Simona Halep was the world No. 2 and one of the favourites for the title in Melbourne. However, the Romanian is now in danger of ending the fortnight as the world No. 4 after Chinese qualifier Shuai Zhang played the match of her life to end her campaign in the first round.

This swing is possible because No. 3 and No. 4 in the world, Garbine Muguruza and Agnieszka Radwanska, both only reached the fourth round last year, and they stand to gain up to 1,760  ranking points, depending on which stage they reach this time. The worst case scenario from Halep’s point of view is that Radwanska makes the final or better, and Muguruza makes the semifinal or better, since this would see her drop to fourth in the rankings.

But this should not even be under discussion, since Halep is an aspiring Grand Slam champion and one of the best players on the planet. As such, she should not be losing first-round matches to players ranked No. 133 in the world – however well they play on the day. What she has to do when she is struggling in these encounters is change her strategy. If being defensive and trying to draw errors from her opponent (the basis of her preferred counterpunching style) is not working, she should step into the court and be more aggressive. On the other hand, if she goes into a match looking to attack and finds she is making too many errors, she should rein in her offensive play and aim to construct longer rallies to encourage her opponent to make mistakes. Halep has shown in the past that she is capable of winning matches by adeptly executing either of these strategies, something that many players cannot do, but her ability to change course between them within a match remains uncertain.

Her problem against Zhang was definitely of the former variety.  Halep made the Chinese journeywoman play as much as she could, only to see ball fly past her time and again as the qualifier hit a seemingly endless succession of winners. To make matters worse, when Halep tried to mix things up with a couple of drop shots, she executed them ineffectively and lost the point anyway. The only way she could really have shifted the momentum of the match would have been to become the aggressor and pin Zhang behind the baseline by hitting the ball hard and deep. Halep did manage to get on top early in the second set, but she failed to sustain her lead for long and seemed to give up eventually.

The only positive that Halep can take from her stunning loss is insight on what not to do in the future, and her fans must hope she will practice scenarios in training in which a change in momentum is required, so that when such a situation arises on the match court, she is ready to wrest control from her opponent. Of course, changing the course of a match also requires a great deal of mental strength. While Halep clearly possesses plenty of determination, her poise seems to desert her in the moments of her career when she is most under pressure. She must learn to handle those moments with more poise, and she must find a way to win when plan A is not working. Otherwise, she may find it difficult to break through for a major title.