| William vs King | 141–266 | 34.64% |
| William vs Jin | 146–244 | 37.44% |
| William vs Law | 138–183 | 42.99% |
| William vs Reina | 150–169 | 47.02% |
| William vs Kazuya | 129–168 | 43.43% |
| William vs Hwoarang | 96–184 | 34.29% |
| William vs Steve | 119–155 | 43.43% |
| William vs Eddy | 96–158 | 37.80% |
| William vs Bryan | 99–135 | 42.31% |
| William vs Dragunov | 89–127 | 41.20% |
| William vs Lili | 91–99 | 47.89% |
| William vs Yoshimitsu | 83–99 | 45.60% |
| William vs Victor | 70–112 | 38.46% |
| William vs Azucena | 84–93 | 47.46% |
| William vs Jun | 90–84 | 51.72% |
| William vs Asuka | 69–84 | 45.10% |
| William vs Paul | 49–102 | 32.45% |
| William vs Lars | 56–92 | 37.84% |
| William vs Heihachi | 52–76 | 40.62% |
| William vs Lee | 54–72 | 42.86% |
| William vs Alisa | 56–62 | 47.46% |
| William vs Feng | 42–66 | 38.89% |
| William vs Xiaoyu | 53–51 | 50.96% |
| William vs Lidia | 49–54 | 47.57% |
| William vs Devil Jin | 34–64 | 34.69% |
| William vs Leo | 54–44 | 55.10% |
| William vs Nina | 44–54 | 44.90% |
| William vs Leroy | 45–49 | 47.87% |
| William vs Jack-8 | 33–55 | 37.50% |
| William vs Raven | 28–59 | 32.18% |
| William vs Kuma | 34–46 | 42.50% |
| William vs Claudio | 29–36 | 44.62% |
| William vs Shaheen | 23–30 | 43.40% |
| William vs Zafina | 19–23 | 45.24% |
| William vs Panda | 12–14 | 46.15% |
Limitations
This data is often requested to give insight into which characters you have more trouble with than others, but it is not particularly helpful for that. The main issue is that it is heavily skewed by how strong the opponents you play are.
For example, this data suggests my worst matchup is clearly vs Reina, but that's just because most of those games are vs Yagami.
There is a way to account for this being worked on. The central idea is to assign each matchup a rating vs you which adjusts based on the result, much like the regular rating but also based on the rating of each player. With this, it would give a better summary of how well you perform vs each character.
In the meantime, this page is here to present the data as requested.