From Tennis.com: Andy Murray says that what has separated the rest of the Big 4 (Novak Djokovic, Rafael Nadal, and Roger Federer) from him is that they haven't fallen into prolonged slumps. "There's an understanding now that if you want to get to No. 1 in the world you can't have a month where you're not winning matches," Murray told the Telegraph. "I did a good job last year when I got to the clay, and since then I've had a lot of good tournaments and got to the last stage of a lot of events. But that month in February-March time hurt me and also the end of the year [when he withdrew from the ATP Tour Finals and Basel because of injuries]. That's the thing that Novak did last year and Roger a few years ago and also Rafa a couple of years ago. They showed that it is possible to win every single event. You need to go in with that mindset and just try and get through matches when you're not playing that well. That's really the goal for this year, to not have those quiet months." I think it's a bit more than that - like winning a major or two.