Entering any tournament as World No 1 brings added pressure, you're the one everyone wants to beat.

But when that tournament is only contested by the world's top eight players, that pressure intensifies.

 Ashleigh Barty will face that pressure when she takes to the court next week in Shenzhen for the WTA finals.

The final marquee event of the season sees Barty look to add this coveted title to her breakout season, in which she won her first Grand Slam title at the French Open.

In our ‘Countdown to Shenzhen’ series, we take a look at what has made Barty so successful this season, and whether her consistency will lead to victory in Shenzhen.

Crafty game is her trademark, but serve really stands out

Since the Australian came back from her indefinite break in 2016, during which she played cricket for Brisbane Heat in the Women’s Big Bash League, the hallmark of her game has been her crafty skills.

Drop shots, short backhand slices and rushing to the net are all tactics that the 23-year-old uses on a regular basis to surprise her opponents. But, the serve, including her exceptional kick serve, can be considered her biggest strength.

So far this year, in the 63 matches she has played, Barty has had a service hold percentage of 79.5 and an ace percentage of 9.3. While these are not career high numbers for her, it is the highest it has been since 2016, where she played only three matches.

The efficiency Barty shows while serving seems to have freed up other aspects of her game because this year the percentage of return points she has won stands at 44.7. This is an improvement of 1.4 percentage points from last year.

All these subtle changes in consistency have resulted in Barty rising to world number one, and in all likelihood, staying near the top of the rankings for a while yet.

But serve has deserted her in recent months

Despite all the improvements Barty has made, she has not won a title since the Birmingham Classic in June this year.

Heading into the fourth round of Wimbledon, Barty was on a 15-match winning streak but her shock defeat to world number 55 at the time, Alison Riske, stopped her in her tracks.  

She has reached two semi-finals and a final since then, but has not been able to lift a trophy at a tournament, including her final loss to Naomi Osaka at the China Open.

Taking a closer look at the most recent matches, it is remarkably the serve which has let her down. In the 22 matches Barty has played since the start of Wimbledon, the percentage of first serves she has got in is 56.29. This is compared to her season average of 57.8.

This does not seem like the biggest drop but of the last 50 break points she has faced, she has lost 19 of those points. In the previous 50 break points, she had lost the point on only 15 occasions.

So there does seem to be a drop off in Barty’s serve in the last few months and she will need to buck the recent trend if she is to sign off the season in style.