Almost three years have passed since Thomas Tuchel was bundled out of the back door at Borussia Dortmund. Having taken over from Jürgen Klopp in 2015, Tuchel was shaping Dortmund in his own image and they were beginning to look like a team who could challenge Bayern's domestic supremecy.

That's before all the pieces came crashing down on a harrowing night in April 2017.

The night Dortmund's team bus was bombed ahead of a Champions League game with Monaco changed things between Tuchel and Dortmund forever. Tuchel's public criticism of UEFA for rescheduling the game just 24 hours later was later compromised by reports that he privately lambasted his players for not being ready to play the next day, seemingly failing to fully take on board the psychological effect the incident had on several members of his team.

The incident, which broke Marc Bartra's arm, had reduced Marco Reus and Gonzalo Castro to tears. Tuchel is reported to have said to a member of his backroom staff the morning after the incident: "How am I supposed to beat Bayern with these wimps?"

The episode piled fuel on a fire that had already been ignited over differences between Tuchel and the Dortmund board relating to transfer policy and the role Dortmund's then chief scout, Sven Mislintat.

The decision to part company was made well before his eventual departure at the end of the 2016-17 season.

'It's not Klopp coming back'

The Dortmund fans are likely to offer Tuchel an indifferent reception, and is little chance of Tuchel and Dortmund CEO Hans-Joachim Watzke sharing a glass of red after the visit of Paris Saint-Germain to the Westfalenstadion on Tuesday.

In fact, Watzke has openly admitted that he will never consider Tuchel a friend, even if there is respect for what Tuchel, the last coach to win any silverware for the club, achieved during his tenure.

"We worked well together for two years, and in the end things got a bit tough," Watzke told DAZN. "We will certainly not become great friends in life any more. But that was three years ago."

Watzke also said emotions "will play no role" when Tuchel leads out PSG. "It's not Jürgen Klopp coming back," added Watzke. "Thomas Tuchel is a great coach. And when I see him, I will certainly greet him and I think he'll do the same."

Haaland vs Mbappe

On the pitch, the visit of PSG is a mouth-watering one. Dortmund's teenage sensation Erling Haaland makes his Champions League debut in black and yellow, while Jadon Sancho, still a teenager until next month, will look to add to his string of impressive performances in Europe's elite club competition.

Kylian Mbappe, who scored a sensational double for Monaco in the aforementioned rearranged fixture in April 2017, will lead the line for the French champions just ahead of Neymar — and Haaland has spoken of his admiration for the Frenchman.

"When I was in Salzburg, I started scoring goals, but I look at Kylian Mbappe banging in Ligue 1 goals, so you can always reach a higher level," Haaland told Bundesliga.com.

Haaland himself has been praised by his new teammates for his professionalism following yet another goal, his ninth in his first six games for Dortmund, in the 4-0 win over Eintracht Frankfurt on Friday night.

"When a young player has been so hyped, with everyone saying how good he is, then he can be a difficult person," said goalkeeper Roman Bürki. "But Erling is a really cool guy, very professional. I'm one of the first at training — but he's always there earlier."