It depends which Nadal. Prime Fed would be licking his chops if he were facing 2019 AO final Nadal.
2019 Nadal was basically DOMINANT at the AO this year until the final. No version of Nadal at the AO (including 2009) was statistically a match for this version of Nadal. Just look at the serve stats.
Clearly, given his vast improvement on the serve and his more aggressive baseline style, 2019 Nadal at AO>>>2005/2006 Nadal at AO.
2005/2006 Nadal was a significant problem for Fed on HC.
Moreover, the irony is that "prime Fed" was less a problem for Nadal than the 2017 Backhanderer.
There are basically three ways to beat Nadal:
1) Hit him off the court (Gonzalez, Soderling, Delpo, Thiem)
2) Counter the heavy topspin FH into the BH and not allow yourself to get pushed around in rallies.
The first strategy is not going to work most of the time. You basically need to be completely in the zone, as all of those guys have been. But none of the guys I mentioned have consistently beaten Rafa, because hitting Nadal off the court means generating lots of UE.
Djokovic since 2011 is the only guy that can really get the job done consistently, mainly because he completely negates Nadal's greatest weapon--the FH into the BH. Fed was never able to do that because of the BH liability, which is why 2017 was so huge.
