The history behind the two teams centers on a controversy from back in 1982, when West Germany eliminated Algeria at the group stage. That year, the Algerians had upset the Germans in the opener, then split their next two games with Austria and Chile, while the Germans had recovered in their second game by routing Chile. The final games of group stage were played on separate days, so by the time the West Germans and Austrians suited to up to play their third game, Algeria had already finished their slate with a 2-1 record and an even goal differential. The Austrians led the group with a 2-0 record and a +3 goal differential, and the Germans were at 1-1 but with a +2 differential. Going into the game, so long as the Germans won by less than three goals, both teams would advance; if Austria won or drew, West Germany would be eliminated and the Algerians would advance.
West Germany scored in the opening ten minutes, and won 1-0. Neither team mounted much of an effort after the opening goal, and the game, forever after known as the Second Anschluss, has become one of the most controversial in the sport's history. Although the game was painfully boring to watch, I've always thought the Germans received a bad rap for what happened; were I to apportion blame, it would go 40% to FIFA, 30% to the Austrians, 25% to the Algerians, and the rest to the Germans. Algeria blew most of a three-goal halftime lead against a pathetic Chilean team, and lost to a mediocre Austrian squad in the previous game 2-0; had they taken care of business, the result of the Anschluss game would have been moot. Austria chose not to attack or play any sort of offense in their final game, not attempting a single shot, and hoping only to keep the score close, which led to the game being famously boring. FIFA deserved the lion's share of the blame for setting up an unbalanced schedule that made such a result inevitable.
But what exactly did the Germans do in 1982 that was wrong or unethical? They had to tread a fine line in that game, where a win by any margin got them to the next round, but a tie eliminated them. Since when has any team been obligated to pour it on and rout their opponents in this situation? They scored the goal they needed.