I don’t know if anyone noticed, but there seems a tradition in Cincinnati that Novak loses finals to Federer every 3 years. He did so in 2009, 2012 & 2015. Now they play once again in 2018.
There is definitely something in Cincinnati that Nole doesn’t like. All other big tournaments with exception of RG, Novak won at least twice. In Cincinnati, he lost all 5 finals he played.
All 3 previous Cincinnati finals against Federer, Nole lost while playing nervously.
Nole also played nervously in his previous matches in the tournament this year, which makes Federer heavy favourite in the final. The only chance for Nole is to tame his nerves and show that he is the better player of the two, so he can hope to be sixth time lucky.