The sample of one particular match is too small to draw conclusions about Isner's chances against Nadal.
Besides, Isner was never close to win this match.
This is not a statistical analysis of his chances against Nadal. There is obviously insufficient data to make a legitimate statistical analysis.
The question remains who are the biggest threats outside the top 4.
It is of no matter that Mr. Isner only played 1 big match at RG against Mr. Nadal.
It was done once and recent enough to make him a threat to do it again, especially as described by me with Mr. Nadal less than his best.
And to say Isner was never close to winning the match is almost laughable.
When was Mr. Nadal close to winning the match? Only in the last set at the end, up 1 break, 5-3.
In terms of sets, one could say that Mr. Isner was close, going up 2 sets to 1 and needing 1 more set for the win.
Regardless, it was the only time anyone has ever taken Mr. Nadal to 5 sets and if anyone outside the top 4 is a threat to Mr. Nadal, it is my opinion that Mr. Isner has to be at or near the top of the list.
You may have a different opinion of who is the biggest threat. It would be nice to see you commit to an opinion with a well reasoned argument. In this thread, I only have seen you be a negative force negating other people's opinions.