The outcome of the match is undecided; both sides still have a chance.
Tips
usage
未定 is the formal/written equivalent of 还没决定 "haven't decided yet." You'll see it on schedules, contracts, and news headlines (e.g. 时间未定 "time TBD"). 未 negates with a "not yet" nuance — different from 不定 ("unfixed, variable").
