Choupo-Moting became an unlikely hero for the Ligue 1 champions at the Estadio da Luz as they progressed to the Champions League semi-finals for the second time in their history.
PSG looked set for another painful quarter-final exit after Mario Pasalic's 27th-minute strike gave Atalanta a deserved half-time lead.
Choupo-Moting had a game-changing effect after replacing Mauro Icardi on the 79th minute mark.
He first played a cheeky pass behind the Atalanta’s defense which Neymar brought down before finding Marquinhos for the equalizer.
The Cameroonian tapped home a Kylian Mbappe cross moments later to complete the Parisians comeback.
Speaking to BT Sport after the game, Choupo-Moting revealed what he said to himself before coming on in the dying embers of the game.
"It was a crazy game. A tough game against a tough opponent. It wasn't easy. Neymar had a great game," the former Stoke City man said.
"I thought when I was coming on, 'We can't lose, we can't go home like this'. I was confident in myself and the team.”
"We had a good feeling in the team. We are enjoying good moments on and off the pitch. We won four trophies but this one is the most important.”
"We believe in ourselves. Everyone knows we have top-quality individuals but we wanted to show team [work]. I'm very happy we did it.”
"It's a long time and we [have] never won the Champions League. With such a great team you have to have this ambition. We will give everything in the next game and continue to believe."