PSG need only draw with Istanbul Basaksehir in their final group game and they will join the winner of United's next fixture against RB Leipzig in the round of 16. Finalists last season, Tuchel will hope to go one better this, but what has been his journey to this point?

1) Humble playing career

He may now be a coach who has won five major honours since arriving in Paris in 2018, but it wasn't always so obvious that Tuchel would ascend to such heights in the game, especially as a player.

A centre-back in the lower leagues of German football with Stuttgarter Kickers and SSV Ulm having been released from Augsburg's youth set-up, Tuchel called time on his playing career at the tender age of 24 due to a chronic knee injury.

"I was angry with my fate," he later reflected. "Ralf Rangnick allowed me to shadow him as an intern and I became manager of the Ulm Under-14s. That's how things started."

2) An eye for talent

PSG today boast a comprehensive structure for player acquisition and have Neymar and Kylian Mbappé - the two most expensive players of all time - on their books. But Tuchel always had a keen eye for a player, even without an infrastructure that allows for sporting directors and a global network of scouts.

At VfB Stuttgart - his next role after Ulm - he was widely credited with improving the games of future Germany internationals Mario Gomez and Holger Badstuber. If those players were already on Stuttgart's book, the same cannot be said for the Mainz squad he later led to a best-ever Bundesliga start in 2010-11 - seven wins on the bounce - and later qualification for the UEFA Europa League.

Underappreciated talents from top academies were a specialty, like Adam Szalai, formerly of Real Madrid; or Loris Karius, who arrived from Manchester City. Eric Maxim Choupo-Moting later worked with Tuchel at PSG, but his most prolific campaign ever remains his first under the German, at Mainz, in 2011 after being allowed to leave Hamburg.

3) Better than Klopp?

Tuchel succeeded the Liverpool-bound Jürgen Klopp as Borussia Dortmund coach in 2015; and although he could replicate his fellow former Mainz manager's back-to-back Bundesliga triumphs in 2011 and 2012, Tuchel's Dortmund were arguably the better side.

Runners-up to Bayern Munich in 2015-16, Dortmund's haul of 78 points would have lifted them to the Bundesliga title in all but three of the previous 52 seasons. Victory over Eintracht Frankfurt in the German Cup in 2017 was Tuchel's first silverware as a coach and Dortmund's first in five years, and he left days later with a win percentage of 63. Klopp's had been 56.3…

4) Dortmund's loss, PSG's gain

After a year away from the game, Tuchel replaced Unai Emery as coach of PSG in 2018. He wasted little time in doubling his personal trophy haul, steering Paris to their Trophée des Champions victory over AS Monaco in his first game in charge.

Two Ligue 1 Uber Eats titles have since followed; as have another Trophée des Champions triumph, and victory in the Coupe de la Ligue and Coupe de France in 2020 which might have been part of a quadruple had former PSG prodigy Kingsley Coman not headed Bayern to a narrow 1-0 victory in August's Champions League showpiece.

Tuchel's 2019-20 season was so impressive that André Villas-Boas, coach of PSG's Classique rivals Olympique de Marseille, broke rank recently and railed against the fact Tuchel had not made FIFA's shortlist for the Best Men's Coach award for 2010.

"Marcelo Bielsa must win a prestige trophy, for his career, for the beautiful football he has shown, everyone recognises it; but for Tuchel not to be in the top five coaches in the world in 2020 is a scandal," he said.

Watch: PSG's most impressive victory last season?

5) 4-3-3 with a twist

Tuchel has been a 4-3-3 coach almost from the start, his Mainz side first employing in 2009 what his PSG did in Manchester on Wednesday. The personnel may have improved ten-fold, but the principles remain the same.

The full-backs - this season invariably Alessandro Florenzi and Mitchel Bakker - regularly push up to create overloads with Neymar and Mbappé up ahead. In control of ball, space is created for those attacking wide men to make or take chances. If possession breaks down, Tuchel makes sure his players push to win it back immediately rather than regroup - the Gegenpressing made famous by Kopp but perfected by Tuchel. They then switch play quickly where space has opened up, with most eyes drawn to the original flank.

PSG's third goal in Manchester was a case in point. Neymar won the ball back deep in his own half, wide on the right. A matter of seconds later Mbappé was clear down the left; he played in Rafinha who cut back to Neymar, and the 3-1 win was sealed from close range, from a move that started far away.

More to come?

"Being nearly pregnant is not being pregnant," Tuchel warned on Wednesday. "That doesn't exist. We've made a big step forward but I'm not going to let a single player think that we've already qualified."

PSG are looking good, though, and Tuchel, from frustrated defender to world-class manager, is a large part of the reason why.