A veteran victory! Kohlschreiber knocks out the highest men’s seed to date, defeating Alex Zverev, 6-7, 6-4, 6-1, 6-3. A 👊 for the biggest win of the day! 📸: @iamcesarin #USOpen #atp #tennis #sports #kohlschreiber #instatennis #instasports #louisarmstrongstadium #usopen50