### Clue: Pair having argument – one side might lose it after this? (5,5)
### Answer: MATCH POINT 
 ### Explanation: Definition: one side might lose it after this
 MATCH(to pair with, as with a matchmaker) **plus**(having) POINT(an argument/a reason in support of an idea or theory).
Defn: After this, one side in, say, a tennis match will lose it (the match) .