Don't forget about trusty command-line options, they can come in pretty handy. -a does a split on whitespace into the @F array.

echo elem1 elem2 elem3 elem4 elem5 | perl -lane 'print $F[3];'
elem4
[download]

And speaking of Davido's thread, if you're shamelessly going for extra XP, there's always the ever-present @ARGV array:

perl -le 'print $ARGV[3]' elem1 elem2 elem3 elem4 elem5
elem4
[download]