Evidence and research from American football, soccer, basketball and baseball pretty conclusively demonstrates that officials favor home teams ... and especially home-team (presumed) favorites. Research suggests that, in most instances, this is not a conscious decision by referees, although some of that almost certainly exists.
Most experts on the subject believe this (in part) explains the "home field advantage" phenomenon. And it's one reason why I attach much greater significance to "road" wins ... especially against teams with winning records.