The Argentina forward scored in Barcelona's 2-0 win over Man United in the 2009 final in Rome, but is expecting a tougher challenge at Wembley Stadium in London on Saturday.
"It's a final, a special game to play," Messi said Monday from Camp Nou Stadium. "There are great memories of Rome, but those are behind us now; this will be a completely different game." Messi hasn't scored since striking twice in the 2-0 win at Real Madrid in the first leg of the semi-finals on 27 April.
The leading scorer in the Champions League with 11 goals, he hopes that playing in Europe again will help end his four-game drought.
Messi and Real Madrid forward Cristiano Ronaldo have both scored more than 50 goals in all competitions this season.
Since Guardiola took charge, Messi has 137 goals in 158 matches for Barcelona. But he acknowledged feeling slightly frustrated at having to sit out the last two league matches with the title already secured for a third straight year.
"I wanted to play but this is also good for me after so many games this season. I'm well-rested and ready to go," Messi said.
One of the key components of Barcelona's possession-based attacking style of football, Messi is hoping his team can win a third European Cup title since claiming its first in 1992, which was also played at Wembley.
Messi has now been at the club for 10 years, but he missed the victory over Arsenal in the 2006 final because of a knee injury. He also has no memories of the team's first European Cup win, with Guardiola in the team, while he was at home in Rosario, Argentina.
"The truth is none. I didn't know it was happening, so I didn't see it: I was five," Messi said.
Guardiola believes he knows the way to get his star player scoring again on Saturday.
"We'll attack from the start. We'll attack, yes," Guardiola said.