Since returning from injury he has won seven from nine tournaments, including a Grand Slam and three Masters 1000 titles.
He is clearly now one of the favourites going into the two remaining Slams this season, alongside Novak Djokovic. He could even regain the world number one spot.
The only uncertainty remaining is his knee. How will he hold up physically? His overall fitness and game has returned to its top level. But under pressure the knee is questionable.
Now Nadal is a little bit closer to Roger Federer's record of 17 Grand Slams. As I said though, how long he can play at this level will be an issue.
Will his chronic knee problem withstand the 3-4 more years at the top he’d need to win those five extra Slams? I’m not sure.
But if he overcomes this knee problem, anything is possible. He has already surprised everyone throughout his career, this year even more so.
We also have to take Federer into account – he could improve his record of Slams. Yes, he has had a poor season and was disappointing at Roland Garros, but clay is his least favourite surface.
Still though, it has been his worst season since 2002, as he has not won a single title. His game appears to be declining, all the while his rivals improve.
Federer could win titles again but he needs to change his game, to accept he is not what he was physically. He’s not doing that right now, and it is a particular worry seeing as he has a recurring right knee problem. But if Federer changes his style of play, he could still get back to the top.
We have been talking about Djokovic and the rejuvenated Nadal resuming their rivalry, but let’s not forget about Andy Murray.
It's easy to do that as he was injured for Paris, but his season started well before that and – provided he is fully fit – he could easily win one or both of Wimbledon and the US Open, on 'home' turf and his preferred location respectively.
The summer is going to be highly competitive for men's tennis, and I for one will be looking forward to Djokovic-Nadal's continued rivalry.