The 44-year-old, now the Bayern Munich coach, is preparing to go head to head with the club with which he is synonymous for the first time.
Guardiola won 14 titles, including two Champions Leagues, during four golden years in charge at the Nou Camp, where he also enjoyed a glittering playing career.
The Spaniard is now hoping to guide Bayern to similar success and finds Barca, now managed by his former team-mate Luis Enrique, standing in the way of a Champions League final appearance.
But, although he is likely to get a warm welcome, he told a press conference ahead of the first leg of this much-anticipated heavyweight contest: “I am here not as a tribute, but I’m here to do my job, with Bayern Munich to reach the final.
“Barcelona was the most important part in my life. Barcelona was everything, but I’m here to win.”
While the Bayern boss is wary of the threat of three-times world player of the year Lionel Messi, he admitted the Argentina international was “just too good” to be stopped.
He added: “It’s almost impossible to play defensively against Barcelona defence. We have to attack. We need to score in Barcelona.
“There is no defensive system that can stop him. Messi is unstoppable. He is just too good. But we can try (and hope that) he does not come into (possession of) the ball.”
Bayern have enjoyed a fine season and the Bundesliga title is already secured, but their form has just tailed off. Borussia Dortmund ended their treble hopes in the DFB-Pokal last week and they also head to Spain after a defeat at Bayer Leverkusen.
In addition to that they have a number of injury issues, but the meeting is nevertheless a mouthwatering one.
Bayern striker Robert Lewandowski is expected to defy facial injuries to play. The Poland international fractured his jaw and cheekbone in the cup defeat by Dortmund but could start wearing a protective mask.
Guardiola said he would leave the decision over Lewandowski until Wednesday, adding: “I’ll talk to him. I want to know how he’s feeling with the mask. Of course we need 11 players who are 100 per cent.
“If he is fit, he will play, sure, but that just depends on his fitness.”
Lewandowski’s presence will give Guardiola’s men a lift with Franck Ribery, Arjen Robben, David Alaba and Sebastian Rode missing through injury.
Boateng faces a tough task as he comes up against Barca’s formidable attacking trio of Messi, Luis Suarez and Neymar but the World Cup-winner is not fazed.
Boateng told the club’s website, www.fcbayern.de: “It’s not just their strikers – Barcelona have world-class players throughout their whole team.
“We know that it’s going to be difficult at the Nou Camp, but we are Bayern Munich.
“We are heading there to get a result. We desperately want to make the final.”
Enrique, meanwhile, insisted the last-four clash was about far more than Guardiola’s return to the Nou Camp, and – speaking at his pre-match press conference – said: “We aren’t going into this as a game against Pep.
“He is the number one for what he has achieved and he’s a friend, but this is such an important game for all Barca fans that it should be more important than any specific people.
“It’s nice for the players to meet Guardiola again, but they know that this game is more important than just that.
“Guardiola knows most of our players but I don’t think that will be decisive. There are many other factors.”
Primera Division leaders Barcelona have their sights on treble success this season and go into the game in superb form.
They have won six in succession in all competitions and not conceded for five games. Their last two results have seen them thrash Getafe 6-0 and Cordoba 8-0.
Enrique said: “I love the word ‘treble’, but there’s still a long way to go.”
Barcelona will be without defender Jeremy Mathieu due to an Achilles injury but are otherwise at full strength.