Manchester United are still wondering what may have been in the first leg.
Manchester United held Bayern Munich to a 1-1 draw in their quarter-final first leg at Old Trafford, but could it have been better?
As the sides prepare for the second leg this week, midfielder Michael Carrick has been discussing Danny Welbeck's big miss, his attempted chip saved by Manuel Neuer when put through on goal.
And the 32-year-old said the miss is still a sore point for the Red Devils.
He told UEFA.com: "That is the one that sticks out for us, it would have been great if that one had gone in but as it happened we managed to go 1-0 up anyway.
"Who knows that would have happened – it was a chance that normally we'd take."
What would be interesting to know is how United's players have reacted to Welbeck personally when discussing the chance.
Have they been patting him on the back and saying 'unlucky', or is it a case of trying to light a fire under him by demanding he does not make the same mistake again, and is more ruthless in Munich?
United will have to be clinical as they will face an uphill challenge in terms of possession, and it would not be a surprise to see them register as low as the 24 per cent of the ball as they did in the first leg.
This means the Red Devils will need to be clinical if they get the same sort of opportunity again, perhaps the encouraging element would be that Welbeck managed to create the space for himself in the first place.
If the ball had fallen to Robin van Persie, out injured, the end result may have been different, but Carrick and Welbeck will have to make sure they play the perfect game on Wednesday and do not leave any 'what could have been's on the field when leaving the Allianz Arena.