Gandalf vs. Sauron

[Iarhen]

Gandalf did have a direct fight with Sauron.

When Frodo put the One Ring on, in a place when they were near the Rauros Falls, he sensed Sauron searching for him and looking at him... Then another voice ordered him to take it off... And suddenly, the 2 voices neutralized each other and everything was silent... And then, Frodo took it off.

That second voice that ordered Frodo to take it off was Gandalf, after he was brought back to life. But after that mental struggle, Gandalf was really weak and had to rest to recover himself.

And Sauron kept on and on after the encounter with Gandalf.

So, in terms of this, I think Gandalf was not able to fight him directly power vs power. Remember, the Valar forbade all the Istari to use their powers to match Sauron's.

And, third. There was NO CHANCE Gandalf could stand up against Sauron with his One Ring on... No way...