I'm pretty sure Blaziken is the best fighting Pokemon in the game. After mega evolving, it has higher physical attack and speed than Breloom and Hariyama, so it rolls through regular trainers very quickly and rarely needs potions. Blaziken also has no shortage of STAB attacks, learning double kick and flame charge (which can revive dead batteries as well as damage opponents) early and high jump kick right after it evolves. source
