**Pre-season optimism can be a dangerous thing, as** [**Manchester United**](/sport/football/teams/manchester-united) **fans have found out the hard way.**
On Saturday Michael Carrick's side suffered a [shock 2-0 defeat at newly promoted Hull City](/sport/football/live/cv629k5zr2jxt), who were by far and away the better side.
Hull, back in the Premier League after nine years away, had never previously beaten United in the top flight.
It is the first time United have lost to a newly promoted side on the opening day.
The consolation for United is that it is not the first, nor will it be the last, opening-day upset.
BBC Sport looks at some of the most shocking opening-day defeats.