Truths, Lies and Tennis Statistics / Matthew Walton / 28 February 2008 / 1

"Magical" Matthew Walton tells us why head-to-head records are the most important tennis stat to look at and how a close examination can lead you to find real betting value

A few weeks back we began to discuss the subject of match betting. We started the debate with a look at 'collateral form'.

This was something of an A-B-C guide to player assessment and bet selection which, put in its simplest terms, explored the theory that if Player A beats Player B and Player B beats Player C, then logically Player A should beat Player C. A rather simple formula but an illuminating one all the same.

There are, of course, many more aspects to match betting than that and here we wish to investigate another of them - head-to-head form.

This is one of the most important factors, if not the most important factor, when a bet is considered. The A-B-C theory works well if players haven't met before but if they have, there is no substitute for the real thing. Proper case histories for us, as both backers and analysts, to pore over.

Now you can approach this study in two ways. Firstly, in-depth analysis.

A detailed examination will cover certain key criteria to determine not just who is going to win the match (that's usually quite straightforward) but whether the price on offer about Player A or Player B is good value. After all, that's what we're concerned with at the end of the day.

Therefore, key questions you will need to ask are :-

1. What surfaces were the previous meetings played on?
2. Did any change in surface(s) radically affect the outcome of a match?
3. How long ago were these meetings? Or the last meeting?
4. What kind of form were the players in at the time?
5. How old, or how (in)experienced, were the players when they met?
6. What is the pattern to their meetings? Did one player dominate early matches or does the other hold the upper hand on recent meetings?

You don't have to examine this information from every conceivable angle, spending hours upon end determining whether a bet is merited. Don't overcomplicate. However, you should at least realise that a systematic way of looking at this data is beneficial and that such statistics are readily available on the web (www.atptennis.com). It will make your betting more disciplined, consistent and, you would hope, successful.

A second approach to the head-to-head issue is actually far easier to comprehend than the points raised above, and often leads to blindingly obvious bets at good 'value' prices.

The point being, if players have faced each other a reasonable number of times (say, four and above) then the win/loss percentage of each player in these previous meetings should be a reasonable starting point in determining their respective prices.

A great example occurred this week in Acapulco. Agustin Calleri was playing Juan Ignacio Chela in a R2 match. The conventional bookmakers initially had it as a 5/6 each of two affair - effectively a toss of a coin.

Betfair had a little more variation as we saw Calleri around (1.75) to (1.87) and Chela being traded at (2.14) to (2.36). In old money, 4/5 Calleri and 5/4 Chela.

Those odds suggest that if played 100 times, Calleri would win 56% of the matches and Chela 44%. Calleri is the slight, but clear, favourite.

Now look at their previous head-to-head form in the table below.

We see that Calleri leads 9:4 on all previous meetings, an even more impressive 9:3 on clay alone and, just for good measure, Chela's last 'win' came by way of a retirement when Calleri was leading!

Given those facts would you say this was a toss of a coin affair? I don't think so.

It's probably over-stating the case to say that if Calleri wins 9 of 12 matches on clay, a 75% strike rate, then he should be around (1.33). But he certainly seemed to have Chela's number on dirt and looked a decent value bet at around (1.80).

The fact they have played so many times gives the form a degree of reliability and given that both players have been in roughly similar form so far in 2008 (i.e. one hasn't been in a monstrous slump) then the crude application of this head-to-head record to the prices on offer makes sense.

Using this logic, Calleri was an obvious bet and duly won, 6-1 in the third set, after being steadily supported throughout the day.

So remember, head-to-head form is the starting point for backers and bookmakers alike. As such it requires special attention. You can go through the detailed, stage by stage approach or you can simply take a view off the overall record.

Either way, this factor is of vital importance when it comes to match betting and you should be fully aware of its use is determing good value bets or lays.

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1. Stitch | 29 February 2008

   Thank for the info. Today if i right understand Almagro win to Acasuso for @1.6 because head-to-head 5-2, because Acasuso play 2 week and Acasuso play double.

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