Wales face a daunting schedule with Millennium Stadium Test matches against Argentina, Samoa, New Zealand and Australia.
The action kicks-off against the Pumas on Saturday with Rob Howley set to name his match-day squad today.
McCusker is desperate to play his part in the mouth-watering clash and reckons Wales can complete an autumn clean-sweep.
"I'm very nervous, it seems to be falling into place but it is out of my hands at the moment," said McCusker.
"All the boys are training well and we have rotated around and everyone is playing everywhere at the moment.
"Obviously we have injuries but if this is my opportunity I need to be able to take it. I have had a bit of game time from the bench over the last couple of years and I will be trying to grab the opportunity, should I get it, with both hands.
"Winning all four is definitely a realistic target, if we take every game as it comes.
"We've chucked some stuff in the bin ready for Argentina, focussed on some areas and we'll bring other stuff out for teams as they come. But if we get momentum from the first game and get off to a good start it's achievable."
But McCusker is well aware of the challenge posed by Argentina, who impressed during the inaugural Rugby Championship.
"They are a very physical team, they have come on through the Rugby Championship as we have seen and they are no mugs," added McCusker.
"We've been watching clips of them and with five minutes to go there were five points in it against Australia. They are definitely able to compete and will take confidence from their first year in the Rugby Championship.
"They have massive emphasis on the scrum, set piece, driving lineouts and they put a lot of effort in around the fringes.
"They're a big strong team up front and have some great backs as well, so across the board there will be a lot for us to handle but the work we do now should put us in a position to deal with that."
And the Scarlets captain reckons the week spent in Poland was ideal preparation for the upcoming internationals.
"When you're in the throws of it, it is difficult to see how it will benefit you getting flogged every hour of the day," added the back-row supremo.
"But when you step back you see we got a lot of work in which would take a couple of months to do around the regional games. You can't always do as much in the week so it was nice to have a week off playing to get a lot of work done.
"There's an air of confidence about the boys. You know how hard you've worked with each other and what you've been through. That resilience gets magnified.
"Before we have said we want to compete with the top nations, now the boys realise that we actually can."