Pep Guardiola has warned Sir Alex Ferguson that Barcelona know how to exploit Manchester United's weaknesses.
The two teams are set to meet in Rome on Wednesday for the UEFA Champions League final and Barca are looking for revenge after last season's semi-final defeat.
Guardiola, who took over at the start of this season, has been studying video footage of the games from 2007/08's last four, which Barca dominated but lost 1-0, while also researching this season's fixtures.
And the Camp Nou coach has spotted chinks in United's armour that his team can take advantage of when they face the holders, live on Sky Sports 1 & HD1.
"The games against United are the ones I watched first," he said in The Sun.
"I saw things where we can hurt United and things where they are dangerous.
"I saw many games from the league this season as well as the games against Arsenal in the Champions League semis.
"We're still studying United's game so I still don't know exactly what I will be saying to my players."
Barcelona, who have already won the Primera Liga and Copa del Rey, can make history by becoming the first Spanish team to win the Treble, if they lift the Champions League.
And Guardiola is well aware of the opportunity, adding: "We have to win at all cost because we can make history."
The Barca boss also added that he would give Thierry Henry and Andres Iniesta late opportunities to prove their fitness as they struggle with knee and calf injuries, respectively.
"We'll decide on Wednesday. I have to see them train before I make a decision," said Guardiola.