$s = "Test-01-xxx";
# Method 1, possibly slow
if ($s =~ /-(\d\d)-/g) {
  print "Pos: $pos - ", pos( $s )- length( $& ), "\n";
}

# Method 2, possibly slow
if ($s =~ /(-(\d\d)-)/g) {
  print "Pos: $pos - ", pos( $s )- length( $1 ), "\n";
}