Ascent to greatness in 2010? He won a tight match with a bucketload of mistakes against Fed at the USO and then proceeded to bend over to Nadal in the final. Winning DC against the French is hardly greatness...
The reason I mentioned the egg was because it can be used to mask the use of EPO, not that it in itself is illegal. Of course, I cannot prove my suspicions but this was the case with Cheatstrong for many years and you can see the result in Oprah's show.
Finally, Djokovic's improvement in fitness had all to do with his success in 2011 and his 2012 AO win in the final.
I didn't really mean the USO 2010 but rather the DC (and what followed). Beating Fed was a small part of it I'm sure (given how many times he lost to Rafa and Fed in 2010 up to that point), winning the DC was another, as well as the improvements in his fitness and the new diet, etc.
But tbh I can think of another player in the top 10 with a career trajectory that makes no sense whatsoever and became the fittest player on tour at age 30. And regardless of what you think of Nole's fitness, he frequently looks out of breath/exhausted after long times on the court or particularly gruelling rallies. It doesn't really fit with magic egg/EPO/similar use.