Marouane Fellaini's late header at Old Trafford two weeks ago was a real killer blow for Hull.
Bringing Manchester United up to the KCOM Staduim trailing by a goal would have been a tall order to begin with, but it's one they'd certainly back themselves to take on on any given night.
A 2-0 deficit though? That's a long way back.
And the stats certainly back that one up. On the 27 previous occasions when teams have brought a lead of two goals or more into the second leg of the semi final, only once have they failed to reach the decider.
That came way back in 1994, when Aston Villa came from 3-1 down against Tranmere to win on penalties.
More recently, Burnley came within a whisker of turning around a three goal deficit in 2009. Having been beaten 4-1 by Tottenham at White Hart Lane, they won the second leg 3-0 at Turf Moor. However, Spurs showed their mettle in extra time, Roman Pavlyuchenko and Jermain Defoe scoring late goals to send Harry Redknapp's side to Wembley.
And even putting aside that statistic, Jose Mourinho's team have tightened up at the back lately. You'd have to go back as far as November 3, and a 2-1 Europa League defeat to Fenerbahce to find the last time they conceded two goals in one game.
The comeback doesn't seem very likely.
