Muller starred with a hat-trick in a 4-0 rout for his country, but was involved in an unsavoury exchange with Pepe in the first half of the Group G tie.
The Bayern Munich ace went down when caught with a flailing arm by the defender. The pair then clashed heads, with Pepe consequently shown a red card.
When asked about the incident, Muller stated: "I would like to see a replay on TV. I hope that it looked okay from my side. I sensed being hit with a fist and it really happened.
"What happened after that I cannot tell exactly. I hope it did not look stupid. I did not want to provoke anything but I don't know 100 per cent how I fared in this situation."
Meanwhile, Muller was naturally pleased with his tally against the Iberian giants.
"Three goals in an opening match against such a strong opponent are something beautiful. One beauty after another.
"I have already made my mark in the world of football in the past four years. I am not a guy who gets scared."
He added: "In the full sun it was extremely difficult, especially without the ball. But we sat back a little bit deeper and then went for the counter. We could have scored more with the chances we had."