Dictionary.net

go around the flank of (an opposing army)

be or do something to a greater degree; "her performance surpasses that of any other student I know"; "She outdoes all other athletes"; "This exceeds all my expectations"; "This car outperforms all others in its class"

get the better of; "the goal was to best the competition"

go around the flank of (an opposing army)

To go or pass around the sides of: used of a military movement.

To extend the flank of one army beyond that of another.