please explain me the federer 's loss in 2015 AO and 2018 USO loses ( serious post )

[skypadq]

so 2015 AO FED : lost seppi in third round

2018 uso fed : lost john milman in R16

i know 2018 uso R16 loses is cause of extream heat

but i think that 's more than that and
i still don 't understand 2015 federer loses named player like a . seppi
i know seppi is ball basher , but ... why old federer so weak at long baseline rally ?

still . myth that fed lost seppi at only third round at 2015 AO ...

 

[PerilousPear]

Fed's an anomaly at the USO after 2011, he can lose to absolute MUGS he never dropped a match or even a set against.

 

[skypadq]

Fed's an anomaly at the USO after 2011, he can lose to absolute MUGS he never dropped a match or even a set against.

yes , fed 's us open after 2011 is worst