Primera Division · Sunday, 18 October 2026 · 02:30. Final score 3–1 (half-time 1–1). Before kick-off we rated it 51% under 2.5 goals — the match finished with 4, so that call missed. That rating was frozen into a version-controlled ledger before the game and has not been touched since.
Open this match in the app →| Market | Yes | No | Our call |
|---|---|---|---|
| Over 2.5 goals | 49% | 51% | Under |
| Over 3.5 goals | 27% | 73% | no pick |
| Both teams to score | 50% | 50% | Yes |
The result model puts Alianza Lima at 70%, the draw at 19% and Atletico Grau at 11%, from expected goals of 2.14 and 0.73.
| Market | Price | Implied | Our rating | Edge |
|---|---|---|---|---|
| Over 2.5 goals | 1.70 | 55% | 49% | -6% |
| Under 2.5 goals | 2.10 | 45% | 51% | +6% |
| Both teams to score | 2.00 | 46% | 50% | +4% |
Implied percentages have the bookmaker's margin removed, so they add to 100 and can be compared with our rating directly. Edge is simply the gap between the two. A positive edge means our model thinks the outcome is likelier than the price suggests — it is not a tip, and a high probability with a negative edge is a poor bet however safe it looks. Prices are a pre-match snapshot from a single bookmaker and move constantly.
Match odds: Alianza Lima 1.30, draw 5.00, Atletico Grau 10.00.
The league sets the starting point. Primera Division has produced over 2.5 goals in 52% of its matches, and that is where a team with no record of its own would sit.
Each side's own record. Alianza Lima have 11 in 28 this season (8 of 14 at home), Atletico Grau 10 in 28 (5 of 14 away). Those records are pulled toward the league rate with the weight of about 24 matches — enough that two or three unusual games cannot swing a rating — giving 45% and 43%.
Last season still counts, briefly. With 28 and 28 games played this season, last season's rates are still blended in and fade out entirely by game 40 — the point at which our testing showed they stop adding accuracy. A single season is part luck, so each club's record is first pulled toward the league average by 34 games' weight. That moves the two figures to 47% and 45%.
The mix. Weighted 40% home side, 40% away side and 20% league — the split that beat every alternative across 30,582 matches of testing — that gives 47%.
Head to head. These sides have met 5 times in three years, producing over 2.5 goals in 20%. That nudges the number 5% of the way toward the head-to-head pattern — deliberately small, because fixtures change more than reputations do — landing on 46%.
Goal expectation. Separately a Poisson model built from attack and defence strength — using real expected-goals data where the league has it — puts this match at 55%, from expected goals of 2.14 for Alianza Lima and 0.73 for Atletico Grau. Folding in 30% of that view gives 48%.
Calibration. Tested against 97,729 past matches, our ratings below 55% have run consistently too pessimistic — a figure in the high 30s, for instance, has come in about four points higher. So ratings in that range are lifted part-way back, giving 49%.
This breakdown is generated from the same inputs the rating uses, so it cannot describe a calculation we did not perform. The full model is set out in the methodology.
| Team | Games | O2.5 | O3.5 | BTTS |
|---|---|---|---|---|
| Alianza Lima | 28 | 39% | 14% | 54% |
| Atletico Grau | 28 | 36% | 29% | 36% |
More: Alianza Lima season stats · Atletico Grau season stats · Primera Division table and form. Ratings are calibrated probabilities, not tips — a 60% call is expected to miss two times in five.