What does Serena Williams need to do to remain World No. 1?

Top-ranked tennis player Serena Williams is a week away from breaking the longest streak as World No. 1. German former No. 1 Steffi Graf is the current holder of that record, having held the top rank for 186 weeks running (and 377 weeks in all).

Williams, currently at 184 weeks, is only two weeks away from surpassing that record, fresh off having matched another Graf record. The German held the most Grand Slam titles at 22, a record that Williams recently matched with her title victory at Wimbledon.

It is now another German player Williams will have to trump, but in a different fashion.

Having made the finals at the Australian Open and the French Open this year, Williams was upset on each occasion – in Australia by Germany’s Angelique Kerber, and in France by Garbine Muguruza. She would take on Kerber again at Wimbledon, this time finally emerging victorious to take her first Grand Slam title of the year after making a third straight final.

It is thus no surprise that Kerber, with a slew of consistently strong performances, is now in hot pursuit of that top ranking, one that was open for the taking for the German at the Cincinnati Masters, or the Western and Southern Open. A title victory at that tournament would have given Kerber enough points to propel her into the top spot. Kerber made the finals of the event, but went down in straight sets to Karolina Pliskova.

That ensured Williams would hold on to her streak a little longer.

Kerber’s road to the finals at Cincinnati was made easier by the absence of Serena Williams, who was sidelined by injury during her participation in the Rio 2016 Olympic Games. The younger Williams sister crashed lost in straight sets to Ukraine’s Elina Svitolina, and visibly struggling with a shoulder injury, chose to sit out of the Cincinnati Masters.

Understanding the Numbers

Serena is currently at 7050 points, and as things stand, ahead of Kerber, who is at 6860. The two are close to each other but fairly clear of the third-placed Garbine Muguruza, who has 5830.

This means that Kerber will need 190 points to overtake Williams for top spot.

The US Open points for women’s singles are awarded as follows:

1R	10
2R	70
3R	130
4R	240
Quarter-Finals	430
Semi-Finals	780
Finals	1300
Win	2000

Intuitively, Kerber starts off on the back foot in the race for the top rank.

Once the 2016 US Open begins, both players’ points from the 2015 Open will cease to be in effect. That puts Kerber, who finished in the 3^rd Round last year, at 6730 points. Williams, who had been the favourite to win the tournament, finished in the semi-finals. That would put her, at the start of the US Open, at 6270 points, behind Kerber.

It is to be noted, however, that Kerber has amassed those points over 21 tournaments, while Williams did so in 13.

As the points currently stand, Williams will need to finish at least at the semi-finals if she is to overtake Kerber. A quarter-final finish would put her at 6700 points, still behind Kerber’s current tally – which means even if Kerber withdraws from the US Open before it begins, she will be World No. 1.

Given Kerber’s current form, this seems like it would be unlikely.

Should Williams finish in the semi-finals of the US Open, that will put her ahead of Kerber at 7000 points. Assuming Kerber progresses to the quarter-finals, that will still put her ahead of Williams at 7160 points. This means that if Kerber reaches even the quarter-finals of the tournament, Williams will need 900 points to make up – meaning that she must make the finals of the tournament.

If Kerber progresses even further, making the semi-finals of the tournament, she will have 7510 points. That will give Williams a 1240-point deficit – so she will have to, again, at least make the finals.

On her current form, Kerber could well reach the final. Should she do so, Williams will need to win the Open to keep her No. 1 ranking.

While Williams has also been in the form of her life – as evinced by her points tally in a little over half the tournaments her closest rivals have played, the 34-year-old has had her brushes with injury of late. It would not be too much of a stretch to believe Williams could in fact win the US Open – a title she has won six times in the past – but statistically, she is on the back foot here, and will need to play a strong, consistent game for victory.