In the sentence "esta mirando jugar a su equipo favorito" jugar refers to a game or match, not the verb meaning "to play" correct
If it meant "to play" it would be "a jugar" correct. Also If he is watching a game of his favorite team, why would "de su equipo favorito" be incorrect
3 Answers
"esta mirando jugar a su equipo favorito" it sounds very strange
he is watching a game of his favorite team
"está viendo un partido de su equipo favorito"
ciao
Yes, "mirar" doesn't sound good when you talk about watching a match, "ver" is better. And you are wrong about "jugar" meaning match or game, it means "to play", so "Está viendo jugar" means "He's watching (them) play". It's more common to say "Está viendo un partido", though.
No..