performed vs should have performed

Hello, everyone!

I have a question about the tense. Could you take a look at the sentences below?

1. I was surprised that the boy performed so well.
2. I was surprised that the boy should perform so well.
3. I was surprised that the boy should have performed so well.

I guess in #1 and #2, my surprise was simultaneous with the boy's performance, even though there could be some a difference of nuance and connotation. In fact, I don't understant their differnce in meaning, but I have learned there is a difference.(This is not my question now.) What concern me now is about #3. My feeble assumption is that the situation in both #1 and #2 setences is probably I went to his concert and watched him and got surprised by his performance. But, with #3, I can not have a obvious picture of in which order events happened. What does #3 mean?

Many thanks in advance!