it's a toss-up
It is a situation in which the outcome cannot be predicted or a decision between two things is very close. I don't know which team will win. Both have done so well this season that it's a real toss-up. Should I take the entry level position, or go back to school? It's a toss-up in my mind.
It's a toss-up.
Inf. It's hard to tell the winner, and it could be won by either player or either team. The game's almost over, and it's a toss-up.