Synonyms for On one's game:

• adv.

  •on a roll (adverb)
  • cooking,
  • on fire,
  • hot.

• Other synonyms:

  •adv
  • smoking,
  • in a groove,
  • in a zone,
  • on a roll,
  • hot-handed.
  •adv.
  • on one's game.