By: Andrew Eccles

When Caroline Wozniacki ascended to the World No. 1 ranking five years ago, she looked like a young player who could quickly rack up a collection of Grand Slam titles — particularly on the hard courts of America and Australia. Her game was defensive at its core; she was a wall at the baseline, wearing down her opponents and pulling the trigger with a backhand that could seemingly do anything. While her contemporaries Victoria Azarenka and Petra Kvitova were still trying to find their way on the main tour, Wozniacki was ruling it.

As of 2015, Azarenka and Kvitova have each won two major crowns – Azarenka in Melbourne, Kvitova on the lawns of Wimbledon.

Wozniacki is yet to claim one.

At 24 years old and with a current ranking of No. 5, Wozniacki is still young for a player who feels like a veteran of the sport. She has been around at the top of the game for so long that it is easy to forget she likely has another six or so more years of battling ahead of her. Easily a contender as the best player yet to have won a Grand Slam title, it is no wonder that the Dane has gathered a dedicated fanbase, and is one of the WTA’s most visible stars.

One question often asked of Wozniacki is whether her game can hold its own in an increasingly aggressive landscape on the WTA Tour. Kvitova, Azarenka and, of course, Serena Williams — along with even the most surprising of Slam winners during her era like Marion Bartoli — are all characterised by aggressive. They either hit the ball hard or can build points that allow them to move forward into the court. Building a wall at the baseline is good, but the best in the game can either break that wall down or find paths around it.

To win, Wozniacki has had to evolve.

While her backhand was always a weapon, it was always easy for opponents to attack the forehand, especially when the Dane’s passive play gave them a ball to attack. For several years this wing went unimproved; Wozniacki was content to find ways to defend it, rather than building it into a secure — or even aggressive — shot of its own.

But most prominently in her year-long resurgence, that forehand has changed. Wozniacki has built more power into the shot, more confidence into her motion. The backhand is still her absolute strength, but the forehand is less prone to break down and can even proactively cause damage.

The confidence with which she hits the forehand has translated into forward motion. It is not enough for the former No. 1 to hit more confidently from the baseline. She must get herself to the net and strike swing volleys and overheads — shots that she can hit with more success than failure. There is still a tendency to back off from the net once she’s hit the volley, but at least one can discern a more aggressive intent. As world-leading as Wozniacki’s fitness is, shortening some points and conserving energy will remain essential over longer and more draining tournaments.

Finally, the game has needed to become one for all surfaces. Objectively, there is no reason why Wozniacki shouldn’t be a better clay courter. All of the essentials are built into how she plays the game: it’s a matter of learning how to execute. In Stuttgart this week, the Dane proved that her game has real clay court possibilities. Her willingness to incorporate the expertise of Arantxa Sanchez Vicario to improve her results is a good sign, one that she wants to keep building her game to hold firm in the higher ranks.

What remains worrying about Wozniacki is a seeming lack of comprehension concerning her own game. When asked about the increased aggression she showed during a hugely successful hardcourt season in the latter half of 2014, Wozniacki repeatedly denied that she was ever a defensive player, arguing that her game had always been aggressive. While she has always shown flashes of the ability to hit balls aggressively, this is extremely different to playing a consistently aggressive match.

If anything is preventing Wozniacki from winning a major title, it is this confusion. Even in the Stuttgart final against Angelique Kerber, Wozniacki paid the price for allowing her opponent back into a match by switching from an aggressive style to start to poisonously passive tennis in the second. Players of Kerber’s calibre, who are perfectly able to powerfully maneuver the ball around the court, will always take advantage if given the opportunity.

Throughout her career, Wozniacki has learned lessons and become a better player because of them. If she can find a way to play consistent aggression, there is no reason why she shouldn’t have a breakthrough and reach the same heights as her contemporaries.

Until then, it is still impressive that one so young has been such a great force in the women’s game for more than seven years. There are few in tennis who cling so grudgingly to matches with the iron will that Wozniacki presents. If you want to get past her, you had better be ready for a fight, and your body had better be at its best.

We love Wozniacki for her magical backhand, but what we love most is that she holds firm — through matches, seasons, difficult years and the quest to defend and reclaim her place on top of the world. Wozniacki has grit, and an everlasting grin. In another seven year’s time, she may well still be a force to be reckoned with.