Grammar question

[yeng]

"My cousin watched a magician perform/performed tricks in a circus when he was in Russia."

If the magician is still performing tricks in the circus, can we use present tense? Or do we have to use past tense because the other verbs are in past tense?

 

[bhaisahab]

"My cousin watched a magician perform/performed tricks in a circus when he was in Russia."

If the magician is still performing tricks in the circus, can we use present tense? Or do we have to use past tense because the other verbs are in past tense?

"My cousin watched a magician perform tricks..."
"My cousin watched a magician who performed tricks..."
Think about that.

 

[2006]

Where do people get the crazy idea that they have to match tenses? Is it mainly from the 'reported speech' mess?