Serena Williams might miss the Women’s Tennis Association finals. They kick off this weekend in Singapore and her knee is causing her pain. But if she doesn’t go, her closest rival Maria Sharapova would only need three wins to end William’s 86-week-long streak as the number one ranked player in women’s tennis.

If Serena Williams spends one more week in the number one spot, she will overtake Martina Hingis on the all-time list for number of weeks at the top. Currently they are joint fourth.

Williams is amazing. In terms of her strength and determination, she has no rival in the current generation.

We used data from the WTA and Match Stat to compare players finishing in the top 20 every year since the Australian Open in 2003, when data at this level was first made available.

Williams owes her success to her outstanding service game. She wins 66 per cent of her points on serve; one in eight of her serves are aces. This forces even talented opponents to go on the defensive when she stands at the service line.

Although she’s not the best at returning, scoring lower than former rivals Justine Henin and Kim Clijsters – she’s still good enough to make it into the top 20 – she has the overall highest points won percentage in the last decade.

Her strong attacking game goes beyond a big serve: on average, every five points she hits a clean winner, a term referring to a shot her opponent has no chance of returning – again the highest percentage on the tour.

