Germany coach Joachim Löw was just as pleased with his team's defensive effort in shutting down world player of the year Cristiano Ronaldo as he was with his forwards in their 4-0 opening World Cup win over Portugal on Monday.

“Naturally it was an excellent first match, we had no option but to win,” Löw told a news conference.

“The team showed the spirit we expect. We dominated the first half in the midfield with fast through balls to the strikers. We were clinical in finishing our chances, we had four goals from about six chances.”

Löw said his players did well to keep tabs on Portuguese forwards Ronaldo and Nani in the Group G match.

“The team played well and didn’t let Portugal have many chances,” he said.

“We played at high pace in the first half to get our chances. It’s important to prevent Ronaldo from getting a run going because he’s very dangerous then.”

Defender Jerome Boateng was assigned to mark Ronaldo.

“Our goal was to disrupt him as soon as he got the ball and Boateng did that very, very well,” Löw said.

Löw, who has been warning his players about the need to preserve energy in what he hopes will be a long tournament for Germany, told his team to shift down a gear or two in the second half after taking a 3-0 lead.

“It was a different match in the second half and the aim was to play economically and keep control of the ball,” Löw said.

“We knew it was going to be hot and it might be even hotter in the next two matches.

“It’s very difficult to run and run under these conditions. It only works when you defend together. We needed everyone to work hard together today and to dig deep to overcome the pain.”

Löw said the injury sustained by defender Mats Hummels did not appear to be as severe as it initially appeared.

“He got a blow to the thigh but nothing was torn,” said Löw. “I assume it’s nothing dramatic.”

Germany captain Phillip Lahm also lauded the collective defensive effort following concerns about the backline going into the tournament.

“We knew we were ready and everyone worked really hard together,” Lahm said.

“Portugal is a super team, ranked fourth in the world. They’ve always gone far in tournaments in the past and they’ve got a really good team. But we worked really hard.

“It was incredibly hot on the pitch. It’s nice to get a great win like this today but we’ve still got a long way to go.”