The ATP’s Gambling Problem

In early August, Nikolay Davydenko played a second round match against Martin Vassallo-Arguello at the Orange Prokom Open in Poland. Davydenko is one of the top tennis players in the world and Vassallo-Arguello is a journeyman who has never reached the final of an ATP event.

By the time the match was over, the world of tennis had its very own gambling problem. Users on, an online betting exchange based in England, played out a pattern of irregular betting that looked an awful lot like someone had fixed the match.

On a betting exchange, users offer bets to each other setting their own odds. Users can either accept someone else’s bet or offer their own. Bets can be placed throughout a match.

Matt is a Betfair user and professional gambler who writes the blog (betters are called punters in England). He bet on that match between Davydenko and Vassallo-Arguello and here’s what it looked like to him.

Several hours before the match, Davydenko opened at 1-5 odds, meaning that he was the prohibitive favorite. One hour later, Davydenko had gone from the favorite to the underdog. His lowly ranked opponent was now the favorite and nothing had happened, no ball had been struck.

Did someone have insider information about Davydenko? Did he have a previously undisclosed injury? Even if he had, according to Matt, “this is very, very unusual, even with a well known serious injury players rarely drift by this much.”

If Davydenko was injured, it didn’t stop him from winning the first set easily and he showed no visible signs of distress doing it. And yet Vassallo-Arguello was still trading as the favorite at the end of the first set. Not only that, but after he broke Davydenko’s serve and went up just 2 games to 1 in the second set, he was trading at incredible 1-17 odds – almost a certainty to win – despite the fact that he was still a set down.

How did this happen? Someone was repeatedly offering large bets with favorable odds for Vassallo-Arguello and it was too much for Betfair users to turn down. They couldn’t resist taking the bets because the odds were so good.

Think of it like this. Andy Roddick and Vince Spadea play a match. Roddick takes the first set easily then Spadea manages to break Roddick’s serve at the beginning of the second set. If someone offers Spadea as a 1-17 favorite at this point, do you take the bet? You’d probably run over your closest friend to get to the keyboard fast enough.

As the betting continued, Matt couldn’t believe what he was seeing: “I sat here laughing in shock at what I was witnessing, my jaw was on the floor.” As far as he was concerned, “this was very blatant match fixing, on a grand scale.” He decided to take action. He called up a fairly senior person at Betfair and explained the irregular betting patterns.

By the time Davydenko retired early in the third set – thereby losing the match – users had bet over $7 million on a second round match in a small tournament in Poland, more than ten times what you’d expect on such an event. Betfair investigated the incident and agreed that the betting was irregular. They took the unprecedented step of voiding all bets on the match.

Here’s what’s bothering me. I can’t think of any way this fix could have worked without Davydenko’s cooperation. Vassallo-Arguello isn’t good enough to beat Davydenko based on sheer will.

Someone might have know before the match that Davydenko was injured – he’d been having problems with his toes earlier in the week – but no serious gambler would have offered bets against him at the end of that first set.

Seven million dollars is a lot of money, by the way. Why would betters draw that much attention to themselves if they wanted to fix a match? In Matt’s opinion, “this has been done several times, so they were not expecting Betfair to void the betting on that match.” They probably thought they could get away with it because it had been done before.

The ATP is currently investigating the incident and they’ve enlisted the help of The British Horseracing Authority. No doubt they have more experience in such matters.

If the ATP decides there was no fix, they need to come up with an alternative explanation if they expect anyone to believe them. Both Vassallo-Arguello and Filippo Volandri have been involved in multiple matches showing irregular betting patterns as you can see in this report on

Matt thinks Betfair should remove players from the betting market if there are repeated cases of irregular betting on their matches. Surely the ATP should take action against a player before it reaches that point.

Betting exchanges are here to stay and tennis has joined horse racing and soccer as a viable betting opportunity. That’s not a bad thing for tennis, but it will be if betters can’t trust that they’re watching a fair match.

Thanks very much to Matt for answering all of my questions.

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