Del Potro leads their previous matches 4-1. Their last meeting was in August 2013. Isner won in 3 sets on a hard court.
Del Potro played well last week though was a little disappointing against Kohlschreiber. His ground strokes were very effective on the grass.
Isner has been playing well and reached the quarter final of the French Open. Thast will have helped his confidence aftwer his injurt problems earlier in the season. He will serve well but he will probably need tie breaks to get sets today.
Some value on Isner as I can see all sets going to tie breaks. Del Potro starts around 1.71 and has drifted a little since yesterday.