Tennis underdog betting: value, odds and losing runs

Research thesis: tennis underdogs, value and losing runs

The appeal of backing underdogs isn’t hard to grasp – in a single wager bankroll can grow significantly – but is this a trap for the greedy and impatient? Should the smart punter grind away gradually with selective favourites and be rewarded for their persistence.

In this article the team have taken a deep dive into the topic of tennis underdogs to examine whether underdog prices can contribute to a disciplined approach to tennis betting profitability. Our approach has been refined since 2013. The research below examines historical underdog markets; the complete public results record begins in 2024. Neither this research nor a longer time horizon guarantees a profit.

Initial Problems & Considerations

Bookmakers apply the highest margins to underdogs. Especially those priced in the 5.00+ range. That mean’s the odds are stacked against punters immediately (in more way than one).

SOLUTION: Sports betting exchanges can help resolve this issue as, for larger matches, the pay-out percentage is close to 100% even for underdogs with just the commission to consider. There is often decent liquidity for ATP tour or higher events. Examples include Betfair, Smarkets & Matchbook. Exchange prices must be compared after commission, with sufficient matched liquidity and applicable settlement rules. Account and jurisdiction requirements still apply.

Favouritism Bias Thesis

It’s well documented that most people back favourites. This is simply due to a human trait known as loss aversion. Cogitative bias offers a significant opportunity for those disciplined enough to overcome it. Remember on exchanges the only competition is other individuals with differing opinions.

TAKEAWAY: An underdog price may offer value when the evidence supports a higher probability than the odds imply. Losing bets and losing periods remain possible, even with disciplined staking. Most sports bettors struggle with this approach and instead prefer the regular gratification of backing favourites where most win (even if this is detriment to their overall attainment in terms of profit achieved)

Indiscriminate Underdog Backing

What if, hypothetically, each and every underdog priced above EVENS (2.00) was backed with a flat stake. Is this an approach that one would expect to yield a positive outcome?

The answer is no however at exchange odds the outcome is a relatively modest loss (net yield -1.50% based on back test data). This is encouraging as with a relatively minor filter this could deliver a profitable outcome over a large sample size.

The table below is based on Pinnacle closing line data (Credit: Pro Tennis Bettor). It again illustrates how positive ROI opportunities typically lie in the underdog sections and not with favourites. 2024/25 data continues to suggest similar trends to that illustrated in the table.

Filtering Underdog Markets

So if the performance of large price underdogs is actually decent – especially with exchange prices and a competitive commission model – then with a few filters this should present an effective tennis betting profit strategy. Tennis Tips UK analyst’s have delved deep into the data for this over the years and have developed multiple filters as to selectively use underdogs to obtain a positive yield.

Club members are the only ones to benefit from this advisory which delivered 115.80% ROI as of early 2024. However for those looking to develop their own tennis betting approach here is some inspiration.

Our proprietary data model considers more than 50 factors and produces a small shortlist for manual human review. The current service provides around two carefully selected match-winner picks per week. The historical research below includes markets used earlier in the service.

Round Attainment Discrepancy

One research area for our team was how underdogs perform at different stages of events and types of tournaments. There is a clear trend suggested in the table below derived from extensive research. This could suggest a filter of avoiding underdogs in the early rounds but backing them as the event progresses to the later stages.

Player Ranking – Excluding Outliers

An area of research by Tennis Tips UK analysts has focused on the concept of only backing underdogs when they have a ranking below their opponent. This may sound like a given but there are occasions when underdogs are actually higher ranked but with exceptionally poor recent form or potential injury issues.

The idea with this theory is that only underdogs that would be expected to be priced that way are backed. Meaning the normal flow of money will back the favourite from recreational punters thinking it’s a formality for the bigger name player to progress.

This frequently leads to unjustified odds drifts for the underdog as bookmakers cover their lability on the favourite should they indeed win. Backing these selections once the drift has occurred could present +EV over a large sample size.

CONCLUSION: This thesis was approved as notable by our analysts and was integrated as a screening factor for club members from early 2024 onwards. There are of course additional factors and exclusions to this rule but it’s certainly worth additional research.

The significance of beating closing line odds

Sustained tennis profit is achieved through backing the correct prices/odds rather than the correct player. Every selection offers value at a certain threshold and the most informed choice isn’t worth backing when odds shorten too far. Closing prices can provide a useful reference when assessing value, but they are market estimates rather than exact probabilities. Beating the closing price does not ensure that a selection wins or that an approach is profitable.

Tennis Tips UK analysts have researched this extensively and have applied filters for club member selections based on an increased probability the advised price represents a peak that late smart money into the market is likely to shorten. The tracking platform used for these club picks documents how effective the selections are at beating the closing price. This is referred to as ‘Avg Diff CO’ and is represented as a percentage.

Enhancing Risk / Reward Profile via Set Handicap

It’s daunting enough trying to pick big price match winners in tennis so surely backing them to win in straight sets is just a step too far? Well interestingly collated Tennis Tips UK data spanning 2013-present paints a different picture. In fact major underdogs win in straight sets (i.e -1.5 or -2.5 Set Handicap dependant on three or five set match format) far more frequently than most tennis punters would imagine.

Clearly this isn’t a universal rule and as always further filter criteria is required but often the straight sets outcome drifts to an unjustified price as money flows in to the match winner market for the firm favourite. This section describes historical specialist-market research. The current club focuses on standard match-winner markets; original set-betting and handicap selections remain accurately labelled in the archive.

As of 2026; this approach has been tested with live bets and the data set is promising. Currently our research is focused specifically on Pinnacle line movements and how sharp money can identify value. The thesis currently surrounds only backing shortening activity when significant and when limits have been increased to a sufficient level. It requires far more testing but could be implemented as a factor for club pick selection going forward.

Tennis Tips UK club members benefit from the culmination of over a decades worth of research when it comes to selecting tennis betting markets through a disciplined, long-term process. Our team have hypothesised over many theories and approaches but our current strategy is to adopt a hybrid approach. Many of the most profitable approaches involve understanding the flow of money and when odds movements are justified (and crucially when they are not).

Current selection process: Our proprietary data model considers more than 50 factors before a small shortlist is reviewed manually by our experienced odds-analysis team. The current club focuses on around two carefully selected match-winner picks per week. This describes the present process; the historical research and markets discussed above retain their original scope. Multiple factors lead individuals to bet on certain players or markets and the recreational punter public still make up the majority of betting volume. This can create pricing differences worth investigating, but it does not guarantee an exploitable edge. Find out more about club membership, including if there are currently any available places, on this dedicated page.

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