Paris Saint-Germain coach Thomas Tuchel let out a scream of joy and relief at the full-time whistle on Wednesday.

It was both a sense of exhilaration and relief for the German, who despite leading the French giants to a domestic treble, was facing the axe had the club not progressed past Serie A side and Champions League debutants Atalanta.

Since the Qatari takeover in 2011, PSG have had four coaches, including Tuchel, and a fifth one looked to be on the cards as the clock signalled the 90th minute.

Atalanta, against all odds, were leading 1-0 courtesy of Mario Pasalic’s 27th-minute opener and fended off waves and waves of attacks by the Ligue 1 side.

PSG looked primed to fail on the biggest stage again and this time, against a side whose net spend since 2002 is still less than the combined €402 million (S$652 million) outlay on Neymar and Kylian Mbappe.

But as the final minute ticked down, Marquinhos fired home via a deflection off Mattia Caldara.

With the resistance broken, Mbappe then set up fellow substitute Eric Maxim Choupo-Moting for a stoppage-time winner, sparking wild scenes at the Estadio da Luz as Atalanta’s players slumped to the turf.

The intensity of Tuchel’s reaction was intensified by the fact that, with an ankle injury he picked up last week, he had been forced to sit on an ice-box and watch most of the game with his leg strapped in a “moon boot”.

Otherwise, the 46-year-old would have piled on his players in celebration as PSG reached the Champions League semi-finals for just the second time.

On sealing their first appearance in the last four since 1995, putting them within a shout of their maiden European Cup, Tuchel said: “Imagine what I would have done if I had two legs.

“Maybe today would be the day you would see me sprint for 40 metres. But it’s the club’s birthday today, exactly 50 years, so we will not forget this birthday for sure. It was absolutely deserved.”

The early curtailment of the French season in April due to the coronavirus pandemic left PSG with a lot of time to think and little action to prepare for the trip to Portugal – they had played only two competitive games since March prior to facing Atalanta – but Tuchel was full of praise for the heart shown by his players.

He said: “It was very difficult to prepare the team. There was no rhythm because there were no games, but I could feel in the last days that the determination, enthusiasm and effort of the group, the quality of the training and the mix between love and hard work, was exceptional.

“For me, it was a deserved win, but if you score so late, it was also luck – but I’m the first one to admit you need luck.”

But luck is also earned and in Mbappe, PSG had a devastating weapon off the bench and whose sheer pace forced the Italians onto the back foot.

The France forward was rated a serious doubt for the game, having suffered an ankle injury in July, but despite being only half-fit, his presence in the second half caused no end of problems.

Atalanta coach Gian Piero Gasperini later called his introduction “decisive”, saying: “There was not long to go and it seemed we had done it, but when you play against some of the strongest in the world at a technical and athletic level, then it becomes tough.”