(Reuters) - Germany defender Per Mertesacker said coach Joachim Loew made the right decision to leave him on the bench on Friday for the first time at the World Cup in Brazil, adding he was happy to be the "water boy and cheerleader" if it helped.

Germany reached the World Cup semi-finals for a record fourth time in a row with a 1-0 victory over France thanks to Mats Hummels' 13th minute header and Mertesacker believes Loew did everything perfectly in the game at the Maracana.

"The coach made all the right decisions and you can't have a more fortunate hand than he did," Mertesacker said of Loew's three changes to the lineup - including putting him on the bench despite his being near flawless in their first four matches.

"He carries the overall responsibility and everyone on the team has a job to do. It doesn't matter to me if I'm the water boy or the cheerleader," added Mertesacker who carried water bottles to team mates during a break late in the match.

Loew went out of his way to praise the 29-year-old Mertesacker for the altruism that underscores Germany's team ethic, saying the Arsenal defender had taken the news that he would not play against France without even a whimper.

"When I told him last night, he said 'Alles klar' coach, I'm here to help the team any way I can'," Loew said. "It was incredibly professional. He's extremely important to the team."

Mertesacker, who has 102 caps, was a bulwark of Loew's defense in their first four matches in which unbeaten Germany gave up only two goals, winning three and drawing one.

"On the pitch you can feel how strong our team spirit is, even if I got to see that from a different perspective today," Mertesacker said.

"We've got to keep that special quality to the end. It has to be like that. Otherwise, we don't have a chance to win the World Cup.

"We've got a great team. The only thing that might have been in short supply at times is that not everyone has always been able to be satisfied," he added, an oblique reference to reports that some leading players, such as Bastian Schweinsteiger, are not as content coming off the bench.

"I've grown so much," added Mertesacker. "This is the third straight World Cup semi-final for a lot of us. We lost the last two. We don't want to repeat that again."