Primera Nacional · Saturday, 31 October 2026 · 20:00. Our rating makes this 41% to go over 2.5 goals, so our lean is under. The Primera Nacional average is 31%.
| Market | Yes | No | Our call |
|---|---|---|---|
| Over 2.5 goals | 41% | 59% | Under |
| Over 3.5 goals | 16% | 84% | no pick |
| Both teams to score | 49% | 51% | No |
The result model puts San Martin S.J. at 43%, the draw at 28% and Gimnasia Jujuy at 29%, from expected goals of 1.34 and 1.05.
The league sets the starting point. Primera Nacional has produced over 2.5 goals in 31% of its matches, and that is where a team with no record of its own would sit.
Each side's own record. San Martin S.J. have 12 in 34 this season (6 of 17 at home), Gimnasia Jujuy 19 in 34 (10 of 17 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 33% and 45%.
Last season still counts, briefly. With 34 and 34 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 32% and 42%.
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 36%.
Head to head. These sides have met 3 times in three years, producing over 2.5 goals in 67%. 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 37%.
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 43%, from expected goals of 1.34 for San Martin S.J. and 1.05 for Gimnasia Jujuy. Folding in 30% of that view gives 39%.
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 41%.
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 |
|---|---|---|---|---|
| San Martin S.J. | 34 | 35% | 6% | 56% |
| Gimnasia Jujuy | 34 | 56% | 21% | 65% |
Our numbers give this match a 55% chance of at least one goal before half-time and 21% of two or more. The Primera Nacional rates, last season and this season combined, are 56% and 20% (this season so far: 56% with a first-half goal, from 612 games). After the break: 71% for a goal and 36% for two or more (league 68% and 28%). San Martin S.J.'s last 50 games had a first-half goal 50% of the time and a second-half goal 70%; Gimnasia Jujuy's last 50, 60% and 82%. A goal in both halves: 42% (league 40%). Highest-scoring half: second 43%, first 27%, level 30% — close to the league's usual split, because team form says little about which half is busier. Team form says less about a single half than about a full match, so these numbers stay close to the league's.
Every match ranked the same way: first half goals today · second half goals today · goal in both halves today · tomorrow.
More: San Martin S.J. season stats · Gimnasia Jujuy season stats · Primera Nacional table and form. Ratings are calibrated probabilities, not tips — a 60% call is expected to miss two times in five.