By Ewan Murray Winning silverware is all well and good but one of the signs of a truly elite team is simply refusing to be beaten. The two things normally go hand in hand, with some of the generational sides of past years having gone on lengthy unbeaten runs en route to glory. An invincible season is perhaps the mark of true greatness, with plenty of Europe’s top sides having boasted such campaigns. From the early 20th century to the modern day, these specific squads have written their name into club legend with their stoic displays and resilience. Here are the ten longest unbeaten runs in Eur…