The Edinburgh Gunners number nine has been selected ahead of the British & Irish Lions player for the RBS 6 Nations Championship opener against France at Murrayfield on Sunday.
The 24-year-old recognises a surprise result and a good performance for Scotland head coach Frank Hadden could leave the Border Reivers man kicking his heels.
However, Blair acknowledges he cannot afford to sympathise with his fellow scrum-half.
Blair said: "It is a great vote of confidence. I have worked with Frank before and felt it was a 50-50 call over who he would play at scrum-half.
"Fortunately for me, I will get the opportunity first and, although Frank has said Chris will have the opportunity in the remaining games, hopefully I can take my chance.
"You cannot afford to think about pressure, because if you worry about things, then you make the mistakes. It's up to me to play my natural game.
"If everybody in the team plays well, it would be hard to drop players in the team.
"But you cannot afford to think about how anyone is feeling.
"It's a fair contest for who plays at number nine and it's my chance this week."
While Cusiter is desperate for a start in the RBS 6 Nations, he insists Blair will have his full backing for the visit of the French.
And the 23-year-old maintains there is no ill-feeling between the pair.
Cusiter said: "I'm obviously disappointed to miss out because I want to be the starting scrum-half.
"I work as hard as I can to put myself in that position, but I am not the only one.
"Mike has been playing well and got the nod this time. It's disappointing, but I still feel I have a part to play in this championship and hope to get the chance to prove that at some point.
"Of course, you have to get behind each other. We both play for the same team and want Scotland to win. The better Scotland are doing, the better for both of us.
"There's no ill-feeling or anything like that because we know the competition in the squad and the game we are playing here.
"I hope there is still a role for us both in the Six Nations and I hope to get the chance at some point.
"This time, I'm on the bench, but I hope to get the chance to prove I should be in the side."