US Open Day 4 summary

Federer bt Youzhny 6-1, 6-7, 4-6, 6-4, 6-2
Rogers and Gavrilova play longest women's match in US Open history
World number one Pliskova beats Gibbs 2-6 6-3 6-4
Seeds Dimitrov and Berdych knocked out, Del Potro through
Nadal wins too