A Top Rank award allows you to very quickly see that a wine is in the top of its class. 

It means that a wine in the top 5 or top 25% of wines in its ranking list, whichever is greater.

A wine's ranking list is based on a minimum set of 15 wines from a single vintage within the smallest wine region that share the same dominant grape variety.

For example:

Wynns Coonawarra Estate V & A Lane Cabernet Sauvignon Shiraz 2016 has been awarded a Top Rank for being ranked #3 of 48 2016 Cabernet Sauvignon blends from South Australia.