Great post there and thanks for the link ! I have always wanted to take a look at wins against top 10 as a key metric while arguing about peak , prime, weak field strong field etc, so good to find it for the top 4 in one place.The Big 4 against top-10:
Fed: 165-92 = 64,2 % (66,3 % at the end of 2012)
Nadal: 123-56 = 68,7 % (66,0 % at the end of 2012)
Djokovic: 108-70 = 60,7 % (56,8 % at the end of 2012)
Murray: 66-53 = 55,5 % (56,0 % at the end of 2012)
I've included 2012 results to show how much a year can mean - Nadal and Djoko went 24-5 and 24-6 respectively, Murray went 5-5 and Fed 4-10 in 2013.
In Fed's best year vs. top ten (2004), he went 18-0 (on his way to beating 24 top ten players in a row as far as I recall).
Obviously, age matters a bit (Fed was up at 71,9 % at the end of 2007). It also matters how much of a prodigy you are.
Fed lost quite a lot early and then won a hell of all lot during 2004-2007 and has had up and down years ever since.
Nadal's winning percentage has been pretty stable throughout the years, probably partly because he mainly met top ten players on clay in his early years (and there, he could always beat anybody!). His best year by far coming in 2013 (82,8 vs. 68,8 in 2010 for example (2006 and 2008 were in both in the mid 70's)
See this article for details on the h2h for each year up until 2012 for the Big Four:
From a quick glance, it does appear that Fed had something going on in 2008 (mono and it's aftereffects) because there is an uncharacteristic dip in the winning % against top 10. Because it is impossible that the field suddenly got strong in 2008 alone and then went back to being weak. It is more likely that Fed's level fell in 2008. Several other interesting observations can be made with this data, but don't want to derail tthis thread from it's topic, maybe subject for another thread.