The champions that counter Cassiopeia hardest in mid lane are Annie (43.4%), Syndra (43.9%) and Xerath (44.69%) — those are Cassiopeia's own pooled win rates. The easiest matchups are Ryze (51.85%), Brand (51.83%) and Swain (51.8%).
46 researched matchup guides for Cassiopeia in mid lane, most-played first. Win rates are Cassiopeia's side, pooled Emerald+ games sampled July 2026.
| Matchup | Win rate | Games | Favour |
|---|---|---|---|
| Cassiopeia vs Sylas | 50.47% | 3,896 | Even |
| Cassiopeia vs Syndra | 43.9% | 3,469 | Syndra favoured |
| Cassiopeia vs Viktor | 46.72% | 3,365 | Leans Viktor |
| Cassiopeia vs Ahri | 45.39% | 2,959 | Leans Ahri |
| Cassiopeia vs Yasuo | 49.86% | 2,517 | Even |
| Cassiopeia vs Katarina | 49.47% | 2,353 | Even |
| Cassiopeia vs Yone | 51.65% | 2,329 | Leans Cassiopeia |
| Cassiopeia vs Vladimir | 46.55% | 2,161 | Leans Vladimir |
| Cassiopeia vs Zed | 48.01% | 2,091 | Leans Zed |
| Cassiopeia vs Ryze | 51.85% | 2,087 | Leans Cassiopeia |
| Cassiopeia vs Hwei | 47.83% | 1,725 | Leans Hwei |
| Cassiopeia vs Malzahar | 45.49% | 1,708 | Leans Malzahar |
| Cassiopeia vs Xerath | 44.69% | 1,703 | Xerath favoured |
| Cassiopeia vs Twisted Fate | 45.9% | 1,623 | Leans Twisted Fate |
| Cassiopeia vs Naafiri | 46.33% | 1,580 | Leans Naafiri |
| Cassiopeia vs Lissandra | 50.13% | 1,564 | Even |
| Cassiopeia vs Lux | 49.67% | 1,506 | Even |
| Cassiopeia vs Akali | 45.24% | 1,428 | Leans Akali |
| Cassiopeia vs Galio | 46.61% | 1,401 | Leans Galio |
| Cassiopeia vs Diana | 47.03% | 1,331 | Leans Diana |
| Cassiopeia vs Karma | 50.75% | 1,326 | Leans Cassiopeia |
| Cassiopeia vs Akshan | 51.14% | 1,318 | Leans Cassiopeia |
| Cassiopeia vs Irelia | 48.05% | 1,311 | Leans Irelia |
| Cassiopeia vs LeBlanc | 45.86% | 1,293 | Leans LeBlanc |
| Cassiopeia vs Fizz | 46.02% | 1,258 | Leans Fizz |
| Cassiopeia vs Talon | 45.86% | 1,182 | Leans Talon |
| Cassiopeia vs Orianna | 46.59% | 1,129 | Leans Orianna |
| Cassiopeia vs Ekko | 48.53% | 1,057 | Leans Ekko |
| Cassiopeia vs Veigar | 45.38% | 1,049 | Leans Veigar |
| Cassiopeia vs Anivia | 49.19% | 925 | Leans Anivia |
| Cassiopeia vs Mel | 50.85% | 879 | Leans Cassiopeia |
| Cassiopeia vs Zoe | 47.76% | 846 | Leans Zoe |
| Cassiopeia vs Aurora | 48.35% | 817 | Leans Aurora |
| Cassiopeia vs Kassadin | 48.17% | 793 | Leans Kassadin |
| Cassiopeia vs Vex | 45.8% | 786 | Leans Vex |
| Cassiopeia vs Qiyana | 47.54% | 732 | Leans Qiyana |
| Cassiopeia vs Pantheon | 49.39% | 658 | Even |
| Cassiopeia vs Swain | 51.8% | 612 | Leans Cassiopeia |
| Cassiopeia vs Ziggs | 47.4% | 595 | Leans Ziggs |
| Cassiopeia vs Annie | 43.4% | 530 | Annie favoured |
| Cassiopeia vs Brand | 51.83% | 490 | Leans Cassiopeia |
| Cassiopeia vs Azir | 51.39% | 467 | Leans Cassiopeia |
| Cassiopeia vs Taliyah | 48.01% | 452 | Leans Taliyah |
| Cassiopeia vs Aurelion Sol | 51.76% | 427 | Leans Cassiopeia |
| Cassiopeia vs Neeko | 49.51% | 402 | Even |
| Cassiopeia vs Locke | — | — | — |