Following their fifth Premier League title in six seasons and FA Cup win at the weekend, Guardiola joined Arsene Wenger and Alex Ferguson as the only managers to win the English double more than once, having also achieved it in 2018-19.
With 11 victories in their last 12 matches across all competitions, Inzaghi's side have also showcased impressive form.
"In modern football, there is before and after Guardiola, it will be very important for us," Inzaghi told a press conference on Monday.
"We will have to be careful to play a team game, we know we will be facing the best, with a fantastic squad and a coach who has marked an era."
Inzaghi added that the match would be the most significant game of his career and was a worthy reward for the club's season as they recovered from a shaky start to finish third in Serie A.
"It will be an evening that repays us for all the efforts made during the year," he said.
"It has been a journey full of pitfalls but, in the last three months, when I have had deeper rotations to play, I think Inter have done great things."
City go into the final as favourites and Inzaghi said his side will have to take whatever opportunities come their way if they were to win the tournament for the first time since 2010.
"The more you see it, the more you understand why they are getting these results, they're a complete team, physical, technical, playing great football, doing great possession and great attacking," he said.
"They have few weak points... we know we will have to be good at taking away some of their possession and covering every inch of the pitch. They are really good at covering spaces."