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WTA Tour

Wuhan Open Reaction — What Were The Odds

Saqib Ali



Andrew Burton

Andrew Burton – TWAA Writer, Commentator and In-House Podcast Guest

The WTA draw at the Premier 5 event in Wuhan boasted a star-studded field, missing only Serena Williams (currently ranked 16). Unfortunately for the tournament, Naomi Osaka withdrew citing a viral infection, although the exertion involved in Osaka’s U.S. Open win and Tokyo final possibly played a part in that call.

Still, 14 of the top 15. A mouthwatering prospect. And none of those players survived to the quarterfinal round.

What were the odds? I’ll come back to that.

If asked about this tournament’s fallen seeds, “Which stories stand out to you and why?”, I would mention Wozniacki, the No. 2 seed, who lost a hard-fought match to Puig, 7-6(10), 7-5, and Daria Kasatkina, who lost to Cibulkova in the round of 16 after winning her first match 10-8 in a final-set tiebreak. Caroline Garcia went down to Siniakova in a third-set tiebreak, and the young Czech followed her win over Garcia by winning two more tiebreaks against Muguruza in the next round.

But my main response went beyond the stories represented by certain players: “How unlikely is that?”

In other words, how unlikely is it that none of the top 14 players entered and seeded in a draw would make the quarterfinals?

I built a Monte Carlo simulation model to do some research. I took as my starting point that a seeded player had, on average, a 75% chance of beating an unseeded one, and that if two seeds met (the R-16 was the only time this could happen), the higher seed would have a 65% chance of winning.

Then I ran the model 10,000 times. Using those starting assumptions, the number of times none of the top 14 players made it through to the QFs? Zero. Didn’t happen.

So I ran the model again, this time 50,000 times. I got one hit this time. So the chances of that Wuhan result (using my inputs) is about 2 out of 100,000. Vanishingly small. (Only 1 of the top 14 making it through happens 1 in 1,000 times).

There are two possible explanations for what I found: One is that the seeds are beaten down by this stage of the season. The second is that WTA matches are even less predictable than I (conservatively) believed. Or most likely, a combination of the two.

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