As it is unclear, based on category placement, etc., exactly what is meant in the question, or in what context it is meant, I will simply speak as an 'Australian Rules' adherent:There would be...
5 if they go in to over time.
Only Four
You can have two players but you have to play 2 squares you can also have four player but 4 squared Johnny Tran
2 to 3 people can play Tennis is formally played by 2people [Singles ] or 4 people [Doubles] .