The Colorado Avalanche are in a hotly contested playoff race. Right now they sit just outside the playoff bracket. They have equal the points to the St. Louis Blues, but the Blues occupy the final wild card berth.
To get to that determination, the NHL uses a tie-breaker system. The first tie-breaker is number of games played. The two teams have both played 78. The second ti-breaker is regulation/overtime wins, ROWs. Colorado and St. Louis have the same amount of those, too.
The third tie-breaker, and the reason the Blues are occupying that spot, is record against each other.