Tennis Favourites the Week Before and After a Grand Slam

The week before a major has a reputation: top names withdraw, others coast, and favourites are said to slip. The week after carries the same story of tired legs and flat minds. I wanted to test both against closing prices, and this study sits alongside my daily tennis predictions as a calendar check on that folklore.

The headline answer is that the folklore does not survive contact with the prices. In the week before a Slam favourites were priced at 65.3% and won 65.4%. In the week after they were priced at 67.1% and won 67.2%. The window where favourites beat their prices most clearly was the Slam itself, at 74.8% won against 73.5% priced. The weakness people expect in the weeks around a major is already built into those numbers.

Window 1Warm-up and hangover weeks priced almost exactly right

Each row sets the favourite's priced chance, with the margin removed, against how often they actually won. The week before a Slam, across 5,581 matches, shows a gap of +0.1 points with a 95% range of ±1.2. The week after, across 5,428 matches, comes out at 0.0. Those two dots almost sit on top of each other.

The Slam row is different. Over 13,771 matches favourites won 74.8% against 73.5% priced, a gap of +1.3 points, and the range there is tight because the sample is large. Ordinary weeks sit in between, at 68.4% won against 67.9% priced.

The usual caveat applies. The week before a major often has fewer top players entered, so favourites are priced shorter elsewhere and longer here, and the chart judges each window against its own prices. Even so, gaps of one or two points remain inside the 95% ranges, so I read this as a market that is roughly right rather than one leaking value.

Window 2Underdogs lose least in the week before a Slam

Turning win rates into money, backing every favourite lost −2.6% in the week before a Slam, −0.9% at the Slams and −2.5% in the week after. Backing every underdog lost −3.9% in the week before, against −6.8% over all matches. At the Slams themselves the underdog bet collapsed to −12.2%.

The base rates explain why. The underdog won 34.6% of matches in the week before a Slam, which works out at fair odds of 2.89. At the majors that fell to 25.2%, with fair odds of 3.97. Best-of-five on the men's side and a deeper field of committed players leave far less room for an outsider.

None of these columns shows a profit. The warm-up week is simply the window where the underdog bet hurts least, and the Slam fortnight is where backing outsiders blindly does the most damage.

Window 3Wimbledon's surrounding weeks lean slightly against favourites

Splitting the tour events by major gives the heatmap some colour. Every Wimbledon cell is negative, with the week before at −0.6 points and the week after at −1.3. That fits what I see on court. Grass rewards first-strike tennis and punishes anyone still moving like a clay-courter, and the swing is short enough that few players settle.

The extremes sit on either side of the calendar. The weakest window was the second week after Roland Garros at −1.8 points across 1,623 matches, when the tour is mid-change from clay to grass. The strongest was the second week after the US Open at +2.2 points across 1,673 matches. The Australian Open row is positive throughout.

These cells are smaller, the smallest at 889 matches, and a week can sit in two Slam windows here. I treat the Wimbledon pattern as a lean worth watching, not a rule.

Window 4ATP and WTA split the warm-up week differently

The tour split is where the two sides part. ATP favourites won 64.7% in the week before a Slam against 65.0% priced, and 66.9% in the week after against 67.3%. Both are small shortfalls. WTA favourites ran the other way, winning 66.1% against 65.6% before and 67.4% against 67.0% after.

The underdog returns follow suit. Backing ATP underdogs lost −2.3% in the week before, and the ATP week after shows the only positive figure in the table at +0.9%. Backing WTA underdogs lost −5.4% in the week before and −5.8% in the week after, close to their ordinary-week rate.

My reading is that some men use the week either side of a major as maintenance rather than a title push, and the price does not quite catch it. The edge is thin and inside the noise, so I would use it to shape a shortlist, not to back every ATP outsider.

Written byEdmund Hartley

I'm Edmund Hartley, based in Bristol, and I write the tennis betting predictions at fixedmatches.vip — where surface, scheduling and form outweigh the rankings.

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