Why is split not up to the task? It seems to me that it is faster than your regex.

#!/usr/bin/perl -w
use strict;
use Benchmark;

my $column = 6;
my $delim = " ";
my $s = qq(a bb ccc dddd eeee fff gggggg hh i jjjjjjjj);

timethese (1000000,{
    'regex' => sub {
        my($result) = $s =~ /(([^$delim]*)$delim?){$column}/;
    },
    'split' => sub {
        my ($result) = (split /$delim/, $s)[$column]
    }
});

__END__
Benchmark: timing 1000000 iterations of regex, split...
     regex: 10 wallclock secs ( 8.90 usr + -0.00 sys =  8.90 CPU)
     split:  9 wallclock secs ( 8.27 usr +  0.02 sys =  8.29 CPU)

Benchmark: timing 1000000 iterations of regex, split...
     regex:  9 wallclock secs ( 8.69 usr +  0.09 sys =  8.78 CPU)
     split:  7 wallclock secs ( 7.87 usr + -0.00 sys =  7.87 CPU)
[download]

The only difference is that split will start numbering your columns from 0, so to get the 6th column you should use $column = 5;