Chelsea need the same again, but with a little more luck, if they are to get past Barcelona on Wednesday night and make it into the Champions League quarter-finals.
Their performance three weeks ago was good enough to provoke 'Miracle in London' headlines the following morning in Barcelona.
Ernesto Valverde's team knew that had Willian's shots been goals, instead of posts, it would have been a 3-1 defeat they came home with.
Lionel Messi celebrates with Andres Iniesta after scoring Barcelona's equaliser in the first leg
Willian had given Chelsea the lead at Stamford Bridge and he also struck the post twice
Chelsea boss Antonio Conte knows he needs a repeat performance, but with better luck
There was recognition that Antonio Conte's team selection and tactics had been perfectly exposed Barcelona's shortcomings. A repeat performance is now required.
At Stamford Bridge, Barca's full-backs had been stopped from getting forward on both sides of the pitch leaving the team with no width.
Sergio Roberto was so busy dealing with Eden Hazard and Pedro, and Jordi Alba so occupied with Willian and the forward bursts of Victor Moses, that they could not threaten at the other end of the pitch.
For all that Olivier Giroud is in form and that Eden Hazard does not enjoy false nine duties, that front three of Pedro, Hazard and Willian asked questions of Barcelona in London that they struggled to answer.
They had also needed to draw breath because of Chelsea's Premier League tempo, embodied by N'Golo Kante who was everywhere as Barcelona mustered just one real chance – the one they took to ruin what would have been an exceptional first-leg 1-0 advantage.
Sport's front page got right behind Barcelona ahead of the second leg at the Nou Camp
'Jump to the quarters' was the headline on the front cover of Wednesday's Mundo Deportivo
That goal takes Barcelona into the second leg still believing they are favourites. In 11 out of 13 previous cases they have gone through after a 1-1 first leg away result.
But if they were wary of the problems Chelsea could pose them before the first leg they are now more conscious of the threats than ever.
There is one big difference between the second leg and the first meeting three weeks ago - Ousmane Dembele now really looks like a Barcelona player.
The French international who signed from Borussia Dortmund last August for an initial fee of 105 million euros rising to 150m has been slowed by injuries and poor form.
He has even looked nervous and out of place in some games, but he seemed to find his wings at the weekend when he ran Malaga ragged setting up the second goal in Barcelona's 2-0 away win.
Andres Iniesta looks set to be fit to start the game on Wednesday and so Dembele might still not start.
But even if the French flyer is on the bench his second-half introduction looks guaranteed. He is now in a very different place from three weeks ago when Valverde left him out of the action as an unused substitute.
When he ruptured a tendon in his thigh in September he had to spend three months on the sidelines. Too much free time is not good for a 20-year-old kid in a new city after a 100m move.
Ousmane Dembele is settling into the Barcelona side following his injury troubles
Chelsea train at the Nou Camp on the eve of their last-16, second leg tie with Barcelona
Conte oversees training at the Nou Camp on Tuesday night as Chelsea prepare for Barcelona
Barcelona offered him his own personal chef so that he would stay off the junk food and tried to ensure he stayed on the right path. Their careful approach is paying dividends and Chelsea might suffer because of it.
The Camp Nou factor could also weigh heavy. Barcelona have played 21 games in their stadium this season and not since Real Madrid in the curtain raiser Spanish Super Cup game at the start of the season has anyone beaten them.
They have won 18 times and kept a clean sheet 14 times. Against a team that has lost its last four away games Barcelona believe that bodes well.
And they have Messi back from his one week paternity leave. Five days after the birth of his first son Thiago, Messi dedicated a goal to his new-born in 2012. And just one day after the birth of his second son Mateo, he did likewise in 2015.
If the thumb is in the mouth on Wednesday it will be because new born Ciro also has his dedicatory goal.
But even that will not necessarily be the end of Chelsea. Another couple of pile-drivers from Willian that, this time, go the right side of the post and Messi goal or not, Chelsea could still be in Friday's draw.
Lionel Messi and his wife Antonella Roccuzzo smile after the birth of their third child