Daniels saved two penalties during a 4-3 shootout win at Bury but also kept out a Phil Jevons spot-kick in normal time and made a string of other saves to keep the Gigg Lane hosts at bay after Kevin McIntyre's 88th-minute strike forced extra-time.
And Simpson was delighted for Daniels, who bounced back from the error which handed Bury the first-leg advantage on Thursday.
"I think on Thursday he made one mistake and he got punished for it but today he has more than made up for it," he said.
"Maybe our goal lived a charmed life today but that was because Luke worked so hard and produced some great saves."
The dramatic win means Shrewsbury will take part in their second play-off final in three years and Simpson believes it would be a great way to go up if they can beat either Gillingham or Rochdale in the Wembley showpiece.
"It's fantastic, unless you're going to be champions of the league, this is a fantastic way to get promotion. I know we're not promoted yet but we're one step closer.
"I don't want to be in the play-offs to make up the numbers. I want to do it properly. It hasn't sunk in yet, there's a lot to look forward to and I've got to put my holidays back a little longer.
"We've got it from sheer guts and determination and showed unbelievable composure at the end.
"We got level on 88 minutes and I hoped we could just nick it, but penalties are all right if you win.
"It was a fantastic game, I am really pleased for everyone concerned with the clubs."
A dejected Alan Knill was left to rue his side's missed opportunities as Bury's season ended in disappointment.
The Shakers only missed out on automatic promotion on goal difference and they were denied a place at Wembley by the invincible Daniels.
He said: "We kept opening them up and I thought sooner or later we were going to score.
"We have had clear-cut chances today and if you don't put them away, you are not going to win games. We did everything we had to do, but couldn't put the ball in the back of the net."
Bury had a golden chance to put the tie to bed when they were awarded the first-half penalty and Knill knows that Jevons' miss was crucial.
"It was significant. All of a sudden you get a chance and don't take it and it gives them a lift .
"If we score I think it might be game over. But that's football.
"I have never criticised anybody for missing a penalty, but I was disappointed for it not to go in."