Giggs, 35, said: "It has been the toughest competition to win.
"Just to get to the final we first had to qualify for the Champions League, which is tough. Then you have got to win it, which is even more difficult.
"And then we had to beat the champions of South America, who had achieved everything we had achieved.
"I have got good memories of the game.
"In parts, Palmeiras were the better team but we managed to get the goal and it was a great feeling because the club had never won it before.
"Prior to the game, the manager reminded us of that and so we were all focused on winning it, just as we are today."
Giggs believes it will be an even tougher competition this season, with United having to play a semi-final as well.
They take on Japan's Gamba Osaka today and Giggs added: "It's a bigger competition now.
"In the past it was just Europe against South America but, now, every continent is involved.
"It would be very special to be crowned champions of the world.
"Obviously, there are two games to play this time, so it's going to be even tougher.
"But it would be great if we did win."