They then dismissed the United States with a strong performance that still left some room for improvement, although Thomas Mueller showed again what a lethal striker he is.

Algeria, masterminded by the wily French Bosnian coach Vahid Halilhodzic and carrying the hopes of the Arab world with them, have impressed with their tenacity and ball skills.

After losing their opening match to Belgium, they overwhelmed South Korea 4-2 in an epic match in Porto Alegre.

In their crucial final group game, a headed goal by Islam Slimani brought them back from 1-0 down against Russia to secure a draw, sending them through to the last 16 and their fans into ecstasy.

Algeria have beaten Germany in the World Cup before, defeating the then-West Germany 2-1 in Spain in 1982. But what followed was a travesty.

After also defeating Chile, Algeria were on the cusp of qualifying for the knockout stages. West Germany met Austria in the final group game, however, with a narrow German victory enough for both teams to go through and see Algeria eliminated.

After an early German goal, the two sides kicked the ball around aimlessly without trying to score again. The cynical display caused global outrage and has gone down in the annals as "the Shame of Gijon".

So the stage is set for a grand showdown in Porto Alegre's Beira Rio stadium, with the winners' reward a quarter-final against France or Nigeria.

Germany can expect a warm welcome in the Rio Grande do Sul capital - the state has a significant population of German descent due to immigration in the 19th century.

While satisfied with Germany's performance against the United States, coach Joachim Loew signalled they needed to tighten up in several aspects of their play. He criticised his team's finishing and said they were also careless in the game's later stages, squandering possession in midfield.

"We lost the ball at the end of the match unnecessarily and that's really dangerous - other teams take advantage of that," Loew said. "We could have had two or three more goals if we had played with a bit more finishing concentration."

Still, with four goals, Mueller shares second in the top scoring stakes with Argentina's Lionel Messi and Brazil's Neymar. Colombia's James Rodriguez, 22, moved to the top of the Golden Boot standings with five goals after his double against Uruguay.

The German machine must be favoured to accomplish their mission.

Algeria will hope Porto Alegre proves propitious for them after their historic battle against South Korea, when their four goals made them the highest-scoring Africans in a World Cup game.

Halilhodzic had complained after the loss to Belgium that his team lacked the fitness to press to the end and needed to be psychologically stronger. But that seems to have been rectified.

Algeria - whose team are built around France-born players from among the former colonial power's immigrant community - were on the back foot against the Russians in the first half, but rallied magnificently in the second.

Slimani is also proving to be one of the players to watch and after his 60th minute goal Algeria had the discipline to hold firm against surging Russian attacks.

"I love it as a coach to see my team fighting like this," Halilhodzic said after the match.

"[Germany] are a huge team. It's going to be very complicated for us. We are small Algeria against big Germany."