The longest active unbeaten streak in soccer came to an end Saturday night as Juventus lost at home to Inter Milan, 3-1. The Italian champion's last league defeat: May 15, 2011, or 49 games ago. By their very nature, such sequences are usually about more than just talent: They require self-belief, resilience, good health and a dose of good fortune. Juventus had plenty of all that, which goes some way to explain the streak. But that doesn't make it any less remarkable.

How does Juventus's streak stack up historically? Actually,...