Here are some examples that may help drive the point home:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @output = qw(OldTop Second Third);
 dd \@output;
 ;;
 unshift @output, 'NewTop';
 dd \@output;
 ;;
 my @otherarray = qw(uno dos tres);
 unshift @output, @otherarray;
 dd \@output;
"
["OldTop", "Second", "Third"]

["NewTop", "OldTop", "Second", "Third"]

["uno", "dos", "tres", "NewTop", "OldTop", "Second", "Third"]
[download]

... a more elegant way ...

I don't know if you will consider this more elegant or not:

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my @output = qw(OldTop Second Third);
 dd \@output;
 ;;
 @output = ('NewTop', @output);
 dd \@output;
"
["OldTop", "Second", "Third"]

["NewTop", "OldTop", "Second", "Third"]
[download]

The disadvantage of this approach is that it requires the construction of a temporary list, which in the case of a large  @output array will be correspondingly large.