Arizona Cardinals vs Los Angeles Chargers — Win Probability

Arizona's 26-14 Win Over LA Defies Model Projection by 21.5 Points

The Arizona Cardinals pulled off a Week 1 upset, defeating the Los Angeles Chargers 26-14 in a result that deviated sharply from pregame expectations. The Cardinals won by 12 points and improved to 1-0, while the Chargers fell to 0-1.

Before kickoff, the model projected a Chargers victory by 9.5 points, with an expected final score of LAC 28.5, ARI 19. That projection aligned with the market line—the Chargers opened as 9.5-point favorites. The model gave Arizona only a 24% win probability, reflecting low confidence in an upset.

What actually happened swung the game decisively in Arizona's direction. The Cardinals outscored the Chargers 26-14, reversing the expected margin entirely. The actual 12-point Arizona margin versus the projected 9.5-point Chargers margin represents a 21.5-point swing from model expectations—a substantial miss.

Breaking this down: the model underestimated Arizona's offensive capability by roughly 7 points and overestimated Los Angeles' scoring by 14.5 points. That combined 21.5-point projection error is significant enough to signal either a fundamental misread of roster strength or game context, or an outlier performance that defied pre-game indicators.

The upset itself was not close—Arizona won convincingly. This was not a narrow one-score escape but a clear-cut victory. The model's 24% upset probability, while non-negligible, still undersold the possibility that materialized. For a brand built on factual accuracy, a miss of this magnitude in Week 1 warrants review of what inputs drove such a lopsided projection in the Chargers' favor.