E.g. tennis and soccer

• Overtime, e.g., and a hint to what spans the two words of each starred answer
• Deciding game
• Tennis "overtime"
• What may decide winner of cup, about right after draw
• Crucial vote
• A shoot-out, e.g
• It settles the score

Wiktionary Word definitions in Wiktionary
n. Something that is used to pick a winner from a tied situation.

WordNet Word definitions in WordNet
n. overtime play in order to break a tie; e.g. tennis and soccer

Wikipedia Word definitions in Wikipedia
In games and sports , a tiebreaker or tiebreak is used to determine a winner from among players or teams that are tied at the end of a contest, or a set of contests.