xG is definitely the best single metric. It tells you if your team is creating real scoring opportunities and not just shooting for the sake of it. It also helps evaluate performance beyond just the final score.
The final score is just one possible outcome in a game full of probabilities. Sometimes, the result reflects the performance; other times, it doesn’t. That’s where xG (expected goals) steps in — to give context.
A team might win 1–0 with one low-quality chance (xG = 0.1) while the other team had 3 big chances (xG = 2.3) but failed to convert. Every shot is a probability of scoring a goal, and there’s randomness to it. Barnes scored a wonderful third goal yesterday, but the exact same chance could repeat next week and he might hit the post instead.
It helps answer the key coaching question:
“Did we play well enough to win, regardless of whether we did?”
Coaches and analysts love xG for exactly this reason. it separates process from outcome. It’s certainly not the only metric we should look at, as we should use it along with xGA, progressive passes, possession, shots, etc.