Cristiano Ronaldo received a rock star's welcome as he returned to training on Wednesday, with Portugal seeking to regroup after their mauling from Germany in their FIFA World Cup™ opener.

The Real Madrid star had a light workout for about 45 minutes before having ice applied to his troublesome left knee: a precaution the medical staff have also taken in previous days. As he left the pitch he signed a child's football boot that was thrown towards him and hurled it back into the crowd before resting in a dugout at the side of the pitch.

Portugal got off to the worst possible start in Brazil with a 4-0 drubbing from Germany on Monday that also saw Pepe sent off for a head-butt and Fábio Coentrão sustain a thigh injury that ruled him out of the rest of the tournament.

FIFA World Player of the Year winner Ronaldo himself endured an afternoon to forget at Salvador's Arena Fonte Nova, where he was over-shadowed by Thomas Muller's hat-trick and avoided answering reporters' questions after the game.

But all that was forgiven in the Campinas sunshine as the side arrived for training at the Estadio Moises Lucarelli. Music blared from loudspeakers and a helicopter whirred overhead as thousands of fans decked out in Brazil and Portugal shirts awaited the arrival of the 29-year-old superstar.

The Portugal captain eventually emerged from a tunnel onto the pitch with the rest of the squad about 20 minutes late, wearing orange boots and a grey and green training top, sending excitement to fever pitch.

As he jogged around the stadium, hordes of teenage girls screamed his name and fans pressed their faces against the wire fence to get a closer look at their hero. Ronaldo, who won the UEFA Champions League with Real Madrid last month, came into the tournament on the back of knee and thigh injuries but Portugal coach Paulo Bento confirmed he was doing well physically after the Germany game.

Father-of-five Nuno Sousa, who is Portuguese but lives in Sao Paulo, brought three daughters and his son along to the training session to see Ronaldo in the flesh, all decked out in the team's colours. "It was a dream for them to see Ronaldo and to see the Portuguese team," he said.

"My father gave me tickets for me and my boyfriend," said Brazilian law student Victoria Martins. "We came because we wanted to see Ronaldo and Pepe. The atmosphere is amazing with everybody cheering. Ronaldo's not my favourite but he's very nice, very generous. He always gives donations and he's good with his fans."

Portugal cannot afford another slip-up when they meet the United States in Manaus on Sunday. The USA beat Ghana 2-1 in their first match in Group G and are on three points alongside Germany. The final matches in the group are on 26 June, when Portugal play Ghana in Brasilia and the United States meet Germany in Recife.