#USOpenSeries Throwback: @JohnrIsner whips a forehand winner vs. Pospisil in R2 of the @bbtatlantaopen on his way to winning his 4th title in ATL. Send a 🔥 for this forehand winner! (🎥: BBT Atlanta Open) #USOpenSeries _ #atp #tennis #isner #johnisner #instatennis #instasports #bbtatlantopen #bbtao