The question presented by this thread is not who is the better player it is “being #1 versus a slam.” And Gaudio upsetting Coria at the FO is arguably a more impressive singular achievement than anything Rios did.
I would have used Brian Teacher as a better example as well:
1. Teacher was a one slam wonder (AO 1980),
2. the one slam was a 2nd rate event at the time,
3. he only had to win six rounds not seven,
4, it has to be among the weakest draws at a Major ever. 3 of 6 opponents ranked 124 - 171. Of the other three no one ranked higher than 33.