Ole Gunner Solskjaer saluted Manchester United's never-say-die stars as they reached the Champions League quarterfinals with a historic 3-1 win over Paris Saint Germain.
United became the first team in European Cup history to recover from losing the first leg of a knockout round tie 2-0 at home on Wednesday.
It was an incredible result given United were without the suspended Paul Pogba as well as nine injured stars including Anthony Martial, Jesse Lingard and Ander Herrera.
But United interim manager Solskjaer insisted he never doubted his players could do the unthinkable in the last-16 second leg in Paris.
"The belief in the boys was just what we hoped for. It was fantastic," Solskjaer told BT Sport.
"You always know it is possible. With this club this is what we do. It's Man Utd. It's the Champions League. That's what it does."
Faced with a daunting first leg deficit, Solskjaer admitted United desperately needed Lukaku's second-minute goal to put the momentum back in their favour.
Once United had opened the scoring, Solskjaer felt the French champions were haunted by the ghosts of their previous failures from winning positions in the Champions League, including blowing a 4-0 lead against Barcelona two years ago.
"It was a great start. We started with a plan to get the first goal, but we didn't expect it to come so soon," he said.
"We wanted an open game with many goals and that's what happened.
"There is always some mental doubt because they (PSG) have had those experiences.
"Our boys are young and fresh which gave us more energy when we needed that goal."
Solskjaer claimed it was the right decision from the referee to award the penalty, although he was nervous when Rashford stepped up to take his first ever penalty for United.
"The referee had a big, big call to make. My staff said the player made himself big, so it's a clear penalty," Solskjaer added.
"I was in the Champions League with Molde and we got a penalty in the last minute and my player missed that and we went out.
"I had to try and calm everyone down. Of course there were doubts. But Rashford, he's 21 and the pressure on the boy, there were no nerves whatsoever, fearless." Solskjaer has had an astonishing impact since arriving from Molde to replace the sacked Jose Mourinho in December.
He is yet to lose a domestic match and has won every away game in all competitions.
After masterminding one of the great European comebacks it is impossible to think he won't get the job on a permanent basis.
When asked about the prospect of taking charge full-time, the Norwegian said: "Until the summer, let's see what happens."