Germany defender Per Mertesacker insists performances do not matter after his side scraped through their World Cup last 16 clash against Algeria with a 2-1 win after extra-time on Monday.

Joachim Low’s side struggled during a goalless 90 minutes in Porto Alegre but reached the quarter-finals thanks to goals in extra-time from Andre Schurrle and Mesut Ozil.

Abdelmoumene Djabou grabbed a late consolation for the north Africans but Germany held on to book a last eight fixture against France on Friday at the Maracana.

Mertesacker responded angrily when asked about Germany’s unconvincing performance and praised the fighting spirit in the side.

"I don't care. We're in the last eight and that's what counts," the Arsenal defender told ZDF.

"What do you want from me? Do you believe there is a carnival team here in the round of last 16? We went over 120 minutes and we fought until the end and I think we won deservedly.

"What do you want? Shall we play beautiful again and then drop out? Seriously, I don't understand these questions."

Germany captain Philipp Lahm admitted his team found it hard against Algeria and lamented a number of missed chances in the second half of the game.

"We knew it was going to be a tough task," he insisted. "They wanted to give everything and that's what they did. And it is clear: If you don't convert your chances, you have to go in extra-time.

"They defended well, had many people around their penalty area and that made it difficult. We were not good on the counter. We were not placed well when we attacked and that led to the chances they had."