I don't think Rizzoli made any mistakes, but you could say that the players were that busy playing they didn't have the time to foul a lot or trick the ref. Unlike Gatusso for instance, a day earlier. This match was about football. Most matches aren't.
As most modern day referees Rizzoli seems a little bit bland though. Kassai, Irmatov: great refs, but as a referee watcher I miss something. These refs are too normal, they aren't weird, there are no stories to tell about them. We will never hear a story about Irnatov hitting a player, or Rizzoli taking on the audience. This is not a complaint of course: you can't complain about someone being good. But still: these great referees make our work redundant. What is there to say, really?
First it was Arsenal, for some ten minutes they attacked like crazy. But they didn't score and since you can't play like that for an hour and a half, they let Barcelona play. It was Barcelona for an hour. Yes they play well, yes they are very well organized and yes they always seem to know what to do with the ball before they get it. A very important thing (you other teams: take note!). The tv commetator spend the hour searching for synonyms for the word Brilliant. But then: what is the use of being brilliant and having the ball all the time if the others score more goals? And brilliant goals too. Maybe Barcelona was a little like Rizzoli: brilliant, but....