Two SQL tables. One contestant has many entries:

Contestants     Entries
Id   Name       Id  Contestant_Id  Score
--   ----       --  -------------  -----
1    Fred       1   3              100
2    Mary       2   3              22
3    Irving     3   1              888
4    Grizelda   4   4              123
                5   1              19
                6   3              50

Low score wins. Need to retrieve current best scores of all contestants ordered by score:

Best Entries Report
Name     Entry_Id  Score
----     --------  -----
Fred     5         19
Irving   2         22
Grizelda 4         123

I can certainly get this done with many queries. My question is whether there's a way to get the result with one, efficient SQL query. I can almost see how to do it with GROUP BY, but not quite.

In case it's relevant, the environment is Rails ActiveRecord and PostgreSQL.