A second-half header from Mario Gomez was enough to give Joachim Low's men a vital victory as they moved joint-top of Group B alongside Denmark.
|GERMANY TO WIN 2-0
|10/1||Germany are 10/1 to beat Netherlands 2-0 with PaddyPower|
"It is very important to start the tournament with a victory. It always is!" Lahm told reporters. "We controlled the match in the first-half, and Portugal had only one chance from Pepe."
Portugal improved after the break, with Nani's cross-shot hitting the bar and Silvestre Varela drawing a fine save from Manuel Neuer, and the Bayern Munich skipper credited Germany's teamwork with helping them grab the win.
"During the second-half we had problems, especially at the end. But that happens. It is all about the team. We know that and we showed that today," the 28-year-old added.
Despite enjoying a prolific season at club level, Ronaldo's impact was limited thanks in part to a fine German defensive display, and Jerome Boateng was quick to praise the efforts of his teammates.
"Everybody knows his [Ronaldo's] class," said the ex-Manchester City defender. "We managed to keep him quiet as a team. The whole team worked very hard offensively and defensively."
Germany's next Euro 2012 game is against Netherlands on Wednesday at 20:45CET.