"If I'm not feeling this good, there's no chance I'll be in finals competing with Rafa".
The second set saw Federer up the ante as he rarely broke a sweat on serve and broke Nadal in the ninth game.
The 6-3 6-4 win over old rival Nadal was his 19th from 20 matches this season, a "dream" like run of form.
The Swiss star missed a large part of previous year due to knee surgery and said that was part of the decision to stay off clay. However, he made amends for his early exit by winning the Indian Wells title, beating Nadal enroute to the final, in which he outclassed compatriot Stanislas Wawrinka. That's not the full story. It was close. I think on the big points I was just a little bit better. Why? Why, I have no explanation.
However, after six months out of the game with a knee injury, he will now take time out to recover from a start to 2017 which has already yielded Australian Open and Indian Wells glory before turning his attention to the French Open. I just think it fell that way today.
For Nadal it was a fifth loss in the Miami Open final, the first of which came against Federer in 2005.More news: Aldean again wins top country music award
He said: "It's disappointing for me that I have been trying during all my career".
Federer said he also had some concern that clay may cause trouble for his knee. "I think I was close enough to win the first set. Physically, emotionally it's been a draining week, so I did very well". It is true that when somebody is coming with that dynamic like him that he's winning a lot, all the things are going your way.
"I will probably stay on hard courts. and get on the clay two weeks before the French, that's the plan for now and hopefully I will play the French and we will see how the build-up is going to go and for me that's essentially when the season really starts".
"I'm not 24 anymore so things have changed in a big way and I probably won't play any clay court event except the French".
Federer is expected to miss events such as the Monte Carlo Masters, the Madrid Open, the Rome Masters and the Istanbul Open as he prepares to launch a challenge at Roland Garros at the end of next month. The Swiss champion believes that the break he had last season has helped him and that another period of rest is necessary to keep him fresh for grass and the following hard court season. "That's why this break coming into clay court season and focusing everything on the French, the grass and then the hard-courts is going to be the key to me".