use strict;
use warnings;
use Devel::Peek 'Dump';
my $token = "ba\x{f1}o";
utf8::upgrade($token);  # force utf-8 encoding and flag.

my $term = "ba\303\261o"; # "utf-8 encoded" but no flag.

warn "Token:\n";
Dump($token);

warn "Term:\n";
Dump($term);

print "match\n" if $token =~ /^$term/i;