Last week’s match-fixing scare has thrown betting in tennis into the spotlight, but it’s not the first time questions about strange betting patterns have arisen. To get some context about whether there’s a problem and how big it might be, we go through the matches that have attracted the most suspicion amongst bookmakers.

British betting exchange Betfair voided all bets traded on the match, an exceptional step that brought the incident to public attention.

There can often be valid reasons for unusual betting fluctuations on a tennis match. The players’ travel schedules, lack of preparation, or genuine injury concerns are all factors that can cause a market to swing. Moreover, suspect betting does not mean one or both players are necessarily involved – details about a player’s physical or mental condition can be known to several people and provide insight into the likely outcome of a match.

Over the last three or four years, several bookmakers have shared information and kept lists of results they consider dubious. This list has grown quite large over time – over 100 matches – but note: a match does not necessarily have to be deemed ‘fixed’ to get on the list. Also included are matches where the outcome is deemed to have been ‘known’ – that is, a bettor or bettors had very valuable knowledge about the likely result which bookmakers and the public did not.

Bookmakers make note of all such matches because of the financial impact they incur as a result, but of course, the public at large is concerned mostly with the possibility of results being deliberately manipulated for gambling purposes. Tennis is more vulnerable than many sports to the impact of match-fixing attempts because one player can single-handedly determine the outcome of a match. Below is a selected list of the matches which have attracted some of the most suspicion.

The allegations range from deliberate fixing to predetermined tanking by a player. Again, these are allegations only, made by those involved in bookmaking or wagering in tennis on a daily basis. No specific conclusions can be drawn about any involvement or intent on the part of the losing or winning player.

The vast majority of suspected matches occurred at lower-level events, helping to assuage worries about problems at bigger events. Women's matches have generally not created the same level of suspicion among the betting industry, and the lower volume of betting makes the potential returns on WTA matches less lucrative. Some  players appear more than once on the selected list, with Davydenko involved in another controversial retirement two years ago. Matches are often also between compatriots or friends, or in some cases between players with very different rankings – the player with the higher ranking usually accused of manipulating the score. However, as noted, the list below is a selection of the matches which appear most suspicious.

The list also includes at least one match where the result was the opposite of the suspected fix. Cold feet or misplaced doubts? Draw your own conclusions.