The Argentinian was broken instantly in his first game, but managed to respond with a break of his own and keep the contest tight between the pair.
However, it was Dolgopolov's powerful returns across the court that managed to secure another break, allowing him to push on and take the lead.
The second set went by the way of serve in the first few matches, but this time, Del Potro managed to get on top with a vital break and push the clash into a third set.
Following his set point, the top seed took control of play on the court, leaving Dolgopolov struggling to make his service games count in the third set.
The Argentinian managed to wrap up proceedings in the third set swiftly to book himself a place in the final four in just over two hours.