Karl-Heinz Rummenigge knows goal difference is the key to the new Champions League format - a lesson Celtic could have done with learning before their trip to Borussia Dortmund.
The Hoops play their third game in the new-look competition this week in Italy against Atalanta. They currently sit in 20th position out of 36 teams after a thumping home win against Slovan Bratislava was followed by a 7-1 hammering from Borussia Dortmund in Germany.
The new league format, with eight games rather than six against a wider spread of opponents, is likely to finish tight on points.
And goal difference - which is now the primary tie-breaker - is likely to be the deciding factor in some team's fates. After thrashing Celtic, Dortmund are now top of the 36-team league, while the Hoops could be FIVE places better off had they not shipped goals for fun in Germany.