Here’s a tough one...From yesterday's matches who gets your vote for the #EmiratesAce of the Day - @delpotrojuan @rogerfederer or @rafaelnadal? Tag your favorite in the comments below and include #EmiratesAce for a chance to win tickets & other prizes! #USOpen #usopen2017 #tennis #arthurashestadium #rogerfederer #rafa #delpotro #grandslam