TACTIX Upset Index — week 40, 2026

Every Monday the TACTIX Upset Index takes the week's settled match results and asks one question: which of them did the model rate least likely before kick-off? For the week ending 4 October 2026, the answer is Ivory Coast 0–1 Cameroon (Friendlies) — the model priced this result at 8.8% — with the full ranking below, as of 5 October 2026.

Calibrated, not hyped — see the full model track record (every league and market, losers included).

Updated 5 October 2026 — covering results from 28 September 2026 to 4 October 2026.

The TACTIX Upset Index for week 40, 2026: Ivory Coast 0–1 Cameroon was the most improbable result in its tracked competitions, priced at 8.8% before kick-off — full graded record published live, as of 5 October 2026.

What was the most improbable result of week 40?

Ivory Coast 0–1 Cameroon was the least likely result between 28 September 2026 and 4 October 2026: the TACTIX model priced it at 8.8% before kick-off. 10 of 294 graded match results finished below the 40% threshold, ranked in the table below.

This week's Index

Each entry is a finished result: the fixture and score, the competition and date, and the probability the model priced that result at before kick-off. Rank 1 is the week's least likely result.

Probabilities are the model's stated pre-match figures for the result that actually happened, frozen before kick-off and graded after full-time.

Priced low, happened, counted

A result priced at 8.8% is not one the model simply got wrong — it is one the model called unlikely, and unlikely things happen on schedule. A well-calibrated model expects outcomes it prices at 20% to land about one time in five, and outcomes priced at 10% about one time in ten. A weekly upset list that was always empty would be the real warning sign: it would mean the stated probabilities were too timid to be informative.

That is the standard every entry here is held to: priced low, happened, counted. The same graded rows feed the live TACTIX scoreboard, where every settled prediction — winners and losers alike — is measured for calibration in the open. An upset earns its place on this page precisely because it stayed on that record.

How the TACTIX Upset Index is computed

Source. Every settled match-result (1X2) prediction TACTIX published, graded after full-time — the same measurement basis as the public scoreboard. This window (28 September 2026 to 4 October 2026) graded 294 match results.

Measure. For each finished fixture in the window we take the model's stated pre-match probability of the result that actually happened. That number was published before kick-off and is frozen at settlement — nothing on this page is a forward-looking prediction.

Threshold and ranking. A result priced below 40% qualifies as an upset. Qualifying results are ranked from least likely upward and up to the ten least likely make the Index; a week with fewer than three qualifiers is reported as a quiet week instead of a padded table.

TACTIX Upset Index — FAQs

What is the TACTIX Upset Index?

The TACTIX Upset Index is a weekly ranking of finished football results by how unlikely the TACTIX model said they were before kick-off. The lower the stated pre-match probability of the result that actually happened, the higher it ranks. It is published every Monday from the same graded records as the public scoreboard.

How is the Upset Index calculated?

Each week's settled match-result (1X2) predictions are graded after full-time. For every finished fixture in the seven-day window we take the model's stated pre-match probability of the actual result; results priced below 40% qualify as upsets and are ranked from least likely upward. Up to the ten least likely make the Index, and a week with fewer than three qualifiers is reported as a quiet week.

Does an upset mean the model failed?

No. An upset is a low-probability outcome happening, and well-calibrated probabilities expect that at a known rate — outcomes priced at 20% should land about one time in five. Upsets appearing at roughly their stated rates is evidence the probabilities are honest. Every entry in the Index was priced low, happened, and counted on the public record.

Where can I see the full graded record?

On the TACTIX scoreboard — live calibration and settled results for every league and market, losers included. The approach is documented on the methodology page and in How accurate is TACTIX?.

More from TACTIX

• Live model scoreboard — calibration and settled results, losers included
• How accurate is TACTIX?
• TACTIX methodology — how the numbers are made
• World Cup predictions

18+. TACTIX previews, predictions and reviews are model-informed analysis — not betting advice or guarantees. Please gamble responsibly — support at BeGambleAware.org.

This post is generated from TACTIX’s match data by our software and checked automatically. How it works →