The 2009 US Open champion needed three hours and 45 minutes to take down Khachanov, 21, in his first participation in the tournament since 2014 after recovering from physical issues that held him back from competing in Melbourne, reports Efe.
"I am so happy to be here after so many years. I had pains everywhere, but I am still standing up," Del Potro said.
Del Potro fired 73 winners compared to Khachanov's 60, proving that the 29 year old was getting back on track.
"These young guys are so strong and I feel like I am getting older, for sure. They are so strong. He hit harder than me the service and the forehand and I had to run a lot, but I think I took my chances to win the match," he said.
The 12th seed Del Potro is set to play world No. 20 Tomas Berdych of the Czech Republic, who defeated Guillermo Garcia-Lopez of Spain 3-6, 6-2, 2-6, 6-3.
The 19th seeded Berdych took two hours and 31 minutes to overcome World No.71 Garcia-Lopez.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
