While Inter have won four straight Serie A titles, their Champions League form has been woeful and they have never come close to matching their two European Cup wins of 1964 and 1965.
A run of eight games without a win in Europe under Mourinho, who seized the trophy with Porto in 2004, looked like it would continue with Dynamo 1-0 up with four minutes to play.
But goals from Diego Milito and Wesley Sneijder after waves of pressure powered Inter from the bottom to the top of Group F with two games to play.
"I do not think about bad things during the match. There was no time for fear," Mourinho told a news conference.
"The most important thing was the character of the team because when you miss so many chances your head can go down. I am sure Inter will qualify, but I don't know if it will be from first or second place."
The outspoken boss was adamant in the build-up to the game that his team would win and thanks to some cool heads in sub-zero conditions they finally showed the fight which typifies their Italian league performances.
"There is an incredible balance in the group between the teams. We've deserved to be the first in the group but everything can change at the end," Mourinho added before praising Dynamo scorer Andriy Shevchenko, who lost his way under the Portuguese at Chelsea.
"I like Shevchenko very much. He is now again the player he was three to four years ago, a great player."
