Steven Naismith says Gordon Strachan's "brutal honesty" has helped the Scotland manager improve the national side's results and performances.
The Scotland striker says that will ensure there is no complacency against Northern Ireland and Gibraltar.
"The manager just says it like it is," he told BBC Scotland.
"On the good side of things, he will praise you as high as he can. On the other side, he'll nail you if he needs to."
Strachan named the Everton striker again in his squad ahead of the friendly against the Northern Irish on 25 March and the Euro 2016 qualifier against Group D minnows Gibraltar that follows.
"We've had some sticky ties against opposition you would have thought we would have comfortably beaten in the past," said Naismith.
"So, going into every game and every qualifier under the manager, that's something he is very much on the pulse on - not to be complacent and just expect the results to come.
"It all starts with hard work and, if you are not having a particularly good game in possession, make sure they guy you are playing against is not having a good game either.
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"That is what a lot of the success has been built on and the players have bought into it."
Scotland lie third in Group D, three points behind Poland and equal on points with Germany and Republic of Ireland.
"As long as I have been in the national set-up, this has been the most optimistic everybody's been and rightly so - more teams do qualify," said Naismith.
"But, if you just look at us specifically, we're playing much better, we're making the right choices in games.
"I think the manager's stripped it all back and just got that fighting spirit that Scottish people have and that is a big part of it."
However, Naismith realises that the Scots still have a battle on their hands to qualify for the finals.
"It is a great feeling among the squad and we know we are only half way and the next half is definitely going to be the tough part of the qualifying campaign," he added.
"I've said from the start - we have been hit with the hardest group. You've got four or five teams genuinely with a chance of getting the top three places.
"It is crucial to win your home games and stop the opposition getting the wins at home."