game on

1 a signal for play to begin in a game or match.

2 said when a contest seems about to begin in earnest.

3 said when you feel that a situation is about to develop in your favour. informal

☞ The expression seems to have originated in the game of darts.

❷2006Sunday Mail (Brisbane) It's game on as Australia's largest car makers, Holden and Toyota, clash with their locally made sedans.