Backticks capture output, but system doesn't. Using exec directly is too much work. open '|-' would be the appropriate choice here.

$ perl -e'
>    my @cmd = ( echo => "foo\nbar" );
>    open(my $fh, "|-", @cmd);
>    print <$fh>;
> '
foo
bar
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Bonus: The shell isn't involved if the command has an argument.