The world number seven broke his opponent twice in each set as he sailed to a 6-2 6-2 victory and a last eight meeting with Ukraine's Alexandr Dolgopolov, who beat Janko Tipsarevic of Serbia 6-3 7-6 (7/2).
"I played better than yesterday, which was pleasing," Del Potro said on atpworldtour.com.
"I hit my forehand really strong and I was confident, able to break serve many times.
"Playing under a closed roof is a little different to the outdoor conditions, but it helps my game and especially my serve."
Del Potro also paid tribute to fellow Argentinian David Nalbandian, who announced his retirement on Tuesday due to a shoulder injury.
"David was a really good player. When he was fit he could beat anyone. He won big tournaments. We have lost a great player on the tour. I wish him all the best in the future," he said.
Second seed Jo-Wilfried Tsonga suffered a surprise 6-4 7-6 (7/5) loss to Croatia's world number 45 Ivan Dodig, who goes on to face Finland's Jarkko Nieminen, a 6-7 (4/7) 6-4 6-2 winner over Polish lucky loser Michal Przysiezny.
In first-round action held over from Tuesday, third seed Milos Raonic beat home favourite Go Soeda 6-4 7-6 (7/0) and Frenchman Jeremy Chardy edged past Marco Chiudinelli of Switzerland 7-6 (7/2) 3-6 7-6 (8/6).