The losing unit Falls Back in Good Order, moving directly away from the winning unit with the highest Unit Strength. If two enemy units have the same Unit Strength, randomly determine which the unit flees from.
However, if the winning side significantly outnumbers the losing side, it will overwhelm the loser. If the Unit Strength of the winning side is more than twice that of the losing side, any losing unit that rolled this result when making its Break test will Break instead.
Note that Unit Strength is worked out at the end of the Combat phase, not at the beginning, and that where you have several units engaged in a single combat, you must add together the Unit Strength of each to determine the Unit Strength of your side.