Calvin Zola grabbed his fourth goal in three matches to give Crewe a dramatic late victory.
"The most important thing was that we tried to win the game. We knew that Darlington would try and throw everything at us and we had to keep going for the full 90 minutes," said Thordarson.
"It was always going to be a competitive game and while we were able to keep a clean sheet I felt that we could also go on and win and get something more from the game.
"I brought on two players in Anthony Elding and Clayton Donaldson who would probably be in the starting XI of most sides in this division.
"This I think shows the strength that we have in the side. Calvin took his goal really well and he was cool and calm; this was very good to see."