If I had to rank Rafa's best ever serving performances, it would be, in that order: US Open 2010, US Open 2013 and US Open 2017. Maybe this year over 2013 even. Something about that tournament brings it out
Too bad his 2010 US Open serve wasn't there to stay though. He changed his grip for that tournament but it gave him shoulder problems so he reverted back and never even tried it again.