A drained Guardiola is to step aside and hand over the reins to his close friend and assistant Tito Vilanova for next season, but will hope to walk away with a 14th trophy from his glittering four-year spell in charge.
The former Spanish international kicked off his trophy-winning run with a 4-1 Copa final win over Bilbao in May 2009.
"His departure is traumatic for me," said Barca and Spain defender Gerard Pique, who returned to the Nou Camp just as Guardiola arrived in 2008.
"I feel I am a much better player thanks to him and the whole team has learned a great deal. He will leave a void, but we'll carry on with Tito and we'll do well. That's football, all eras come to an end."
Barca have already won the European and Spanish Super Cups and the Club World Cup this season, but missed out on the major prizes in the closing weeks of the campaign.
They were denied a fourth consecutive La Liga crown by Real Madrid, and fell to Chelsea in the Champions League semi-finals, before Guardiola's shock decision not to renew his contract.
There has been criticism in some quarters at the way Vilanova's appointment was announced at the same news conference in which Guardiola said he was leaving, leading to speculation of a rift between the two.
"Guardiola's relationship with Vilanova is fantastic," midfielder Cesc Fabregas said earlier this week. "Hearing these comments from outside isn't good. It hurts us."
Barca will have to make a number of changes in defence with Eric Abidal, Carles Puyol and Dani Alves all ruled out with injury, while striker David Villa will not recover from his broken leg in time.
Barca and Bilbao have lifted the trophy 48 times between them, and have been two of the most entertaining teams in Spain this year with their focus on attacking football.
However, they will have to contend with a freshly laid pitch at the Calderon in Madrid, replaced after a rock concert there on Sunday night, and a political storm stirred up by the president of the Madrid regional government.
Basque and Catalan nationalists among the two sets of fans whistled the national anthem in 2009, and Esperanza Aguirre's suggestions on Tuesday that the final should be suspended if it happens again caused widespread condemnation.
Bilbao head into the final with some trepidation after their crushing 3-0 Europa League final defeat to Atletico Madrid two weeks ago.
"We need to be more relaxed from the start, not as nervous and as rushed with our passes (as we were in Bucharest)" Bilbao's leading scorer Fernando Llorente said.
"We deserve to win this Cup. We have managed to put behind us the disappointment of the other final. If we can play to our best and nullify Barca, we are capable of beating them."
The club, who only field players of Basque origin, are also concerned their inspirational and eccentric coach Marcelo Bielsa may not stay beyond the end of the season as he remains silent on his future.
A two-week break after the end of La Liga will help the Bilbao players as fatigue took its toll in the season run-in and they lost four of their last five matches in all competitions.