Dejected United leave Rome in ruins | Night to remember for Barcelona | Ronaldo and Co lose their way | Debate: Did Ferguson get his tactics wrong? | How Barcelona rated | How United rated | How the action unfolded | Rooney: we lost to best team | Henry reaps reward with new friends | Simon Barnes | Patrick Barclay | Giles Smith | Tony Cascarino | Key moments | Graphic: errors cost United dear

Manchester United deserved what they got. If you cannot expose that vulnerable Barcelona back four with all the attacking talent at United’s disposal in Rome, something is badly wrong.

Sir Alex Ferguson’s side simply didn’t gel. They underachieved from back to front. Cristiano Ronaldo was frustrated and no wonder. United cannot expect Ronaldo to win games for them single-handedly all the time. He needed others to chip in. But where was Wayne Rooney? Defending, mostly — one of the greatest attacking talents on the planet was modelling his game on Park Ji Sung.

Ferguson was understandably desperate to nullify Lionel Messi and Thierry Henry, because you cannot allow them to take on defenders one on one. An early example of the danger came when Messi got half a yard on the defence and blasted narrowly over the bar.

So Rooney found himself doing defensive duties. He’s more willing than most forwards to track back and help out — perhaps too enthusiastic. He struggled to get into the game and didn’t offer enough up front. There are times when a player must ask for help from a team-mate and say: “You keep an eye on him, I’ve got to push forward.” On such a big stage, United couldn’t afford Rooney drifting in and out of the contest. He needs to learn to be braver.

There comes a point in a match, if your team are losing or you’re anonymous, when you have to make your own mind up. Great players make great decisions. They don’t need to rely on a manager telling them what to do on the touchline. Rooney should have placed less focus on his defensive duties early on, even if Ferguson hadn’t given him permission to do so.

It was especially frustrating because Barcelona looked so vulnerable at the back. Carles Puyol was a red card-in-waiting if United had only run at him more often.

There was nothing fundamentally wrong with Ferguson’s tactics — after all, United started strongly — but they were knocked out of their stride by Samuel Eto’o’s goal and lost confidence, appearing to be panicked because they were looking to get rid of the ball too quickly at the back.

The main problem was that United stood off again and again. Without the suspended Darren Fletcher and the injured Owen Hargreaves, they did not have a protector to patrol the space and make tackles in front of the back four — the role that Michael Essien performed for Chelsea in the semi-final against Barcelona.

Still, it was strange after the terrific season that United have had for them to be showing an opponent so much respect. And bizarre that they did exactly what everyone knows you mustn’t: give Barcelona’s playmakers the time and space to pick their passes. United will look back on last night with huge regret.