Game that goes into overtime, e.g

• Game that goes down to the wire
• Sudden-death game, say
• Rail bent badly across one in situation marked by tension
• Brilliant playing - with energy - but losing line in tense moment
• Tense situation
• Anxiety-evoking close game, for example
• Very close game that could cause fans to ruin their manicures: Hyph
• Close contest

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of nail-biter English)