The Daily Express quoted Murray, as saying: "It's hard to put your finger on because there's such a lot of stuff goes on. Obviously, things off the court can affect it. You just have to try to make sure you keep all your problems and issues out of it and go back to focusing on tennis, which is my job. Hopefully I'll be able to do that."
At 22, it would only be natural for Murray to ponder at times on his split with girlfriend Kim Sears, whose life he shared for four years - even though there are rumours of a reunion.
But perhaps more enfeebling for Murray is his unfortunate involvement in the devilish politics of a sport he single-handedly carries on his young shoulders.
High on that list is his personal spat with former Davis Cup captain John Lloyd over Murray's attempts to balance his own career objectives and the national cause.
Murray said: "You know the kind of stuff that goes on off the court within tennis. There's the Davis Cup and I've said a few things about the LTA, too. There are a lot of things that can be mentally draining and which you can get subconsciously annoyed or upset about. (ANI)