Never explain, or defend yourself at the table. This is important, DONT DO IT.

Just say "yeah this site is totally rigged"

or "wow, the same thing happened to me just the other day"

If they call you a fish and start swearing at you say "sorry I am not very good" or "I don't know what it is but I can't fold suited cards" or "I just had a feeling". The other option, which I usually use is just to say nothing. It doesn't matter if you made the right play or made a bad play and got lucky.

Defending your moves may actually make the other player realize he made a mistake.