Federer and Nadal didn’t even play good chunk of 2016, which is why Murray got to #1. Also, Novak slumped badly by his standards.
With that being said, Murray will eventually exploit Federer’s massive 6 year age handicap. Also, if #116 Donskoy and #302 Haas can beat Federer, then Murray can beat Fed. Fed is vulnerable in a best of 3 setup. Fed has owned Murray in the slams, however. Murray’s only win over Fed at a slam was in 2013, the year a ton of people owned Fed. And Murray still needed 5 sets to win that match.
Speaking of 2013, I never realized how bad that year really was for Fed. Age, back pain, and that crappy racket really caught up to him.
Here are all of Fed’s 20 seasons’ worth of records against the top 10, sorted by the most games below .500
2013 4-10 -6
2000 3-7, -4
2008 7-10, -3
2016 1-4, -3
1999 1-4, -3
1998 0-1, -1
2001 5-5
2011 10-9, +1
2003 9-5, +4
2009 15-10, +5
2002, 10-5, +5
2012 16-9, +7
2015 15-6, +9
2010, 16-6, +10
2014, 17-5, +12
2017,14-2, +12
2007, 17-4, +13
2005 15-2, +13
2006, 19-4, +15
2004, 18-0, +18
In 2016, I remember an announcer saying that Jack Sock had a career year up to that point because he registered 4 wins against the top 10, the first year that he had multiple wins against the top 10. Jack Sock now has 9 career wins against the top 10.
Here is a list of some of the players that have multiple seasons with 10+wins against top-10 opponents:
Federer 12
Nadal 8
Djokovic 7
Borg 6
Sampras 6
Lendl 6
Murray 5
McENROE 4
Connors 4
Becker 3
Edberg 3
Agassi 2
Note. 7-time slam champion Wilander only has 1 season with 10+ wins against top-10 opponents.
Murray has 5 seasons with 10+ wins against the top 10. That is remarkable. I never would have guessed that. Murray is way underrated by most, IMHO. I was guilty of this myself.
Edit: Federer was 14-2 vs top 10