How to sort dates in Perl?

use Data::Dumper;
my @dates = ( "02/11/2009" , "20/12/2001" , "21/11/2010" ) ;
@dates = sort { join( '', (split '/', $a)[2,1,0] ) cmp
join( '', (split '/', $b)[2,1,0]) } @dates;
print Dumper \@dates;