Spain got their campaign started on Friday with a 3-3 draw with European champions Portugal, who needed a last-gasp Cristiano Ronaldo free-kick to salvage a point at the end of an absorbing contest.
That game came just days after Lopetegui had been fired as a result of accepting a future role with Real Madrid, leaving the national team’s preparations for the tournament in crisis.
"I think everybody who has been playing football a long time knows football always gives surprises," Queiroz said in his pre-match news conference at the Kazan Arena.
"There's always something new and we know things change constantly. It was quite a peculiar situation, but it's over.
"It's sort of ironic because I fought so much and I really tried to have him as a player and I really fought so hard.
"Now he will be my opponent. I admire him very much, I really admire him. These sorts of decision are always hard, I know him well, he is a very skilled person and he is the right person to unite them, a team which could've been divided.
"I think picking him as a coach is something which shows how valuable he is as a man and coach. We saw against Portugal the team played like a united team, as if nothing happened."
Iran have suffered a blow, however, as Queiroz confirmed defender Rouzbeh Cheshmi will miss the rest of the tournament with a muscle injury.
"Unfortunately, it's one of those bad news," he said. "Rouzbeh is out. It was a small accident in a training session. He is injured."
Nevertheless, midfielder Masoud Shojaei suggested the injury would spur Iran on to play better in honour of their "brother".
"He's a key player, as he showed previously. He played well, he showed how good [he is] despite the criticism that existed," Masoud said.
"Of course we miss him but we have many good players to fill in. One thing we need to remember is that we are a team and that comes from our culture.
"We are not just a team, we're a nation, a family, and I believe we have already shown in difficult situations that we are usually united and able to achieve the best result.
"I believe this helps us. Maybe it's a bad situation for him, he helped us on the pitch, but he helps us to become stronger. We know our dear brother is not with us and we shall show what he means to us by playing better."