Cristiano Ronaldo and Deco earn most of the plaudits for Portugal but the man who really makes the quarter-finalists tick in midfield is Armando Petit.

Coach Luiz Felipe Scolari took a lot of flak for picking the 1.75-metre tall midfielder in his squad for the tournament after Petit had an injury-plagued season with Benfica.

"The call was criticised a lot," said the 31-year-old, whose surname is Goncalves Teixeira and who takes the French nickname Petit from the country of his birth.

"I knew I had to work to be in shape for the Euro. (But) I'm giving a good response," he said ahead of Thursday's quarter-final with Germany.

"The coach trusted me, I've got nothing to prove but I showed I can be here," said Petit, who played a key ball-winning role as Portugal swept to victory over Turkey and Czech Republic to reach the last eight.

"It's normal. I was out (of action) for a long time. I didn't do the pre-season, then I had an injury to my knee and another in my foot. I managed to work well to be in good shape here."

Scolari relies heavily on Petit for his mobility and speed to win the ball for Portugal's attacking quintet of midfielders Deco and Joao Moutinho, wingers Ronaldo and Simao Sabrosa and striker Nuno Gomes.

"Petit distributes play very well, he provides the conditions for Deco and Joao Moutinho to have room to create," Scolari said last week.

"He's tactically perfect and always well-positioned to defend."

Petit, who helped Portugal reach the finals in 2004 as hosts, said he did not expect to have special duties in marking Germany captain Michael Ballack.

But he added: "If he plays I'll be concerned with his movements.

"We must remember the team is not just Ballack but if he comes into my zone I won't make it easy for him.

"He's good at turning up in the area and shoots well with both feet. We are prepared for that."

Petit, a free kick specialist who has won 56 caps and scored four goals since his 2001 debut against Ireland, said concentration was the key.

"Germany know how to exploit mistakes, we can't commit any and we must exploit theirs. We have to be concentrated," he said.

"They had difficulties against Austria but they are a compact and aggressive team."

Germany did not qualify for the last eight until their 1-0 win over Austria on Monday, five days later than Portugal.

Petit had said he would retire from international football after the tournament but he is now considering staying on for a third World Cup in 2010.