Using The Game State Spreadsheets To Profile Matches In-Play

Skype: @TennisRatings

I thought I'd do a piece about the new Game State spreadsheets, which have given me a number of new edges in the market since I completed the research for them recently.  

With a variety of stats available based on starting price and projected hold variables  it's given me a lot of concrete data for many entry points, allowing me to enter (or refuse to enter) with absolute confidence that my approach will yield positive expectation results in the long run.

Bearing this in mind, I thought I'd analyse a recent match which had a lot of highlighted entry points - Jana Cepelova vs Elena Vesnina, a real swingathon with Vesnina starting favourite at around 1.50.

Elena Vesnina started the match as a solid favourite...

Set 1:-  

Cepelova broke immediately to lead 1-0.  Players fitting the profile of Cepelova lost the first break lead 121/196 times in the first set in 2014 (61.7%), which is both above the WTA average and also the April-June average.  However, Cepelova held without facing a break point all set, and broke Vesnina again to take the set 6-2.  Laying Cepelova would have yielded a loss in set one.

Set 2:- 

6-2 set winners lost the second set 30.2% of the time, which is slightly worse than the WTA mean of 34.7%.  32.5% of second sets after a 6-2 first set went to a scoreline of 6-0 to 6-2 for the set 1 winner.  53.2% of second sets ended either in a tight win (6-4/7-5/7-6) for the set 1 winner, or a win for the set 1 loser.   The most common score for 6-2 winners of set 1 was 6-2 to them again in set 2 (16.6%).  6-2 first set winners won 57.8% of tiebreaks in the second set.

Naturally this information is very useful for both betting and trading.  Furthermore, in matches which players fitting the profile of Cepelova won the first set, their opponent took the first break of the set 89/189 times in 2014 (47.1%) and recovered a set and break (50/100 times) 50.0%.  11/31 times similar players to Cepelova lost at least one break from a set and double break up.

Therefore 73.5% of the time (139/189) similarly profiled players to Cepelova either took the first break of the set, or recovered a set and break deficit.  We can use this information to structure our trades, knowing that this percentage is above the WTA mean, and so is both the first break of set 2 and recovery of set and break percentage.  With lower risk and a higher success percentage, it also seems logical to stake more from a set and break position than at the start of the set two, although both seem reasonably viable.

Cepelova took the first break of set 2 to lead *4-3.  She lost a set and break lead to go back on serve three times in 2014, to Serena Williams, Rebecca Peterson and Yulia Putintseva, but took the second set in all of these matches to win in straight sets.

Vesnina recovered a set and break deficit four times in 2014, and won the second set in three of these matches (Casey Dellacqua, Bojana Jovanovski and Francesca Schiavone).  She actually won the match from a set and break down against Jovanovski.  She lost in straight sets to Madison Keys from recovering a set and break.

With a bigger stake averaging down when Cepelova was a set and break up, her losing this lead creates a green position in set two.  

Statistically in 2014, 79/142 (55.6%) players fitting Cepelova's profile won set two when they lost a set and break lead in the set to go back on serve, and they won set three 34/63 times (54.0%).  Overall they won the match 79.6% of the time, which gives implied odds of 1.26, which we can use to create positions based on market prices.

Furthermore, players fitting Cepelova's profile lost serve when serving for set two 39.5% of the time on all surfaces, which is a few percent bigger than the WTA mean.  Considering this, we can look to lay Cepelova when serving for set two (and the match) and she was broken serving for the match, generating further profit.

After several further breaks, the second set went to a tiebreak.  Price wise, players who fitted Cepelova's odds range profile won the tiebreak 50.0% of the time, and 6-2 first set winners did so 57.8% of the time, so it seems reasonable to assume that Cepelova's chances will be somewhere between the two percentages, so a very very slight favourite.  However, with WTA first set winners winning tiebreaks 120/210 times (57%) this is no worse than expectation, and provides us with a slight edge laying Cepelova for the tiebreak, which she loses 7-5, to generate a positive position for us.

Jana Cepelova lost a set and break lead twice, failing to serve out the match in set two...

Set 3:-

Players that won set 2 7-6 had a tough time in the 2014 WTA season, losing the set 52.4% of the time.  The most common set 3 score was 6-2 to the set 2 loser, followed by 6-3 to the set 2 winner.  Players that won the second set 7-6 only won the 3rd set in a dominant 6-0 to 6-2 scoreline 32.1% of the time.

For the first time, Vesnina took the lead in the match, breaking to lead the set 1-0.  Players fitting her profile lost a break lead 49.0% of the time, and one break from a double break lead 43.2%.  The percentages are slightly below average for the first break in set 3 for the WTA, but higher for a double break.  On this basis, laying Vesnina a break up in set 3 doesn't seem a superb position, but laying her a double break up would be.

As it happens, Vesnina lost her break lead immediately, but laying her in this position wouldn't be a recommended play to generate long term expected value.  A bad value winner, if you like.

Based on starting prices, Vesnina would be around a 57% favourite to win the tiebreak in set three, and from a small sample 61.5% of set 2 tiebreak winners won the third set tiebreak, so the Russian would fancy her chances.  My play here would be to back her when 3 points down in the tiebreak, to create a low risk, high reward position.  Cepelova took the set 7-4, without a 3 point lead being obtained.

Overall, we created a number of entry points with positive expectation, with only one loser (set 1), for a positive result on the match.  

Game State Spreadsheets:-