The South Americans are looking to win a third trophy in as many years after successive Copa America titles, including beating Argentina in last year's final.
Chile defeated Portugal on penalties to set-up a meeting with the world champions in St Petersburg on Sunday.
"We have proven our value," said Vidal.
"We have beaten Argentina and Portugal, the European champions, if we win on Sunday, we will prove we are the best team in the world."
Vidal, who plays his club football in Germany with Bayern Munich, hoped this tournament would be good preparation for the 2018 World Cup in Russia.
He added: "We have reached this final with our spirit and attitude - this is a waiting room for the World Cup - and if we win on Sunday that will show where we are."
Germany have the youngest team in Russia with the average age of their squad just 24.
However, they have produced some impressive performances as the tournament has gone, notably beating Mexico 4-1 to reach the final.
"A lot of work has gone into our wins," said Germany boss Joachim Low. "We couldn't pre-empt reaching the final as some players had little experience and you couldn't calculate how they'd react.
"We've become a team over the last few weeks. They know there is work ahead and they are ambitious enough to beat Chile."
A Germany victory on Sunday would complete a successful couple of days for the country after the Under-21s beat Spain 1-0 to win the European Championship on Friday.
Yes, during the group stage as the two sides shared a 1-1 draw.
Arsenal forward Alexis Sanchez opened the scoring in the sixth minute of the Group B encounter before Lars Stindl equalised just before half-time.
Germany went on to finish top of the group as Chile finished second.
It looks like the top scorer of the tournament is going to be a Germany player.  Tim Werner is currently leading the way (three goals, one assist), with Leon Goretzka (3, 0) and Stindl (2, 0) also in contention.
Portugal talisman Cristiano Ronaldo has two goals and one assist but he won't take part in the third-place play-off with Mexico having already gone home to spend time with his new-born twins.
Chile midfielder Arturo Vidal believes beating Germany in the Confederations Cup final in Russia will prove they are the best team in the world.