The renewal of Chelsea's rivalry with Paris Saint-Germain in the Champions League this week sees Liam Rosenior make a quick return to France, just two months after he left Strasbourg for Stamford Bridge.
Rosenior, 41, was appointed by Chelsea in early January on a six-year deal on the back of a solid body of work over 18 months at Strasbourg, as well as the close links between the two clubs run by the BlueCo consortium.
It is hard to imagine the former Fulham, Hull City and Brighton right-back would have been hired by one of the biggest sides in the Premier League without that controversial relationship, but Rosenior still made a major impression in Alsace.
He led Strasbourg to European qualification last season and laid foundations that have been built on by his successor Gary O'Neil, who has taken the team to the French Cup semifinals while they are one of the leading contenders to win the Conference League.
Rosenior got a young side – in which almost the entire squad is aged 23 or under – playing a sophisticated brand of football, with high pressing, man-to-man marking and players very comfortable in possession.
Strasbourg were one of just two teams to beat PSG in Ligue 1 last season, with a 2-1 victory in May that admittedly came after Luis Enrique's side had been confirmed as champions.
And Rosenior's last visit to the Parc des Princes in October ended in Strasbourg claiming a 3-3 draw – they had been 3-1 up at one point.
"We were playing against the best team in the world, full stop. I think they are a credit to this league," was how the Wandsworth-born coach described PSG.
This fixture became a genuine rivalry for a time in the last decade, when the clubs met in the Champions League knockout phase in three straight seasons, from 2014 to 2016.
The first was a quarterfinal won by Chelsea, but PSG triumphed in the last 16 in the two years that followed.
The most recent encounter was in the Club World Cup final last July, when Chelsea won 3-0 against a tired PSG in sapping conditions at the MetLife Stadium in New Jersey. Now they meet in the last 16 once again.
"These are the games you live for, games that you come into football for," Rosenior said after the draw was made late last month.
HOLDERS ON VERGE OF CRISIS?
Rosenior has so far lost three games out of 15 in charge of Chelsea, all of them against Arsenal.
A 4-1 win at Aston Villa last Wednesday left the Blues fifth in the Premier League, and Saturday's extra-time victory at Wrexham took them through to the FA Cup quarterfinals.
A much-changed team for that game is likely to have little in common with the side that takes to the field in Paris, as Chelsea look to oust the reigning European champions.
PSG currently look more vulnerable than they have in a long time, with their performance in a 3-1 home defeat by Monaco on Friday being heavily criticised.
"The champions have stopped responding", was the headline in sports daily L'Equipe, which described Luis Enrique's team as being "on the verge of a crisis".
That might sound like an exaggeration, but Rosenior's description does not really hold right now with PSG having been beaten four times already in 2026.
Their lead over Lens at the top of Ligue 1 is just one point, and in Europe they appear a level below the likes of Arsenal and Bayern Munich.
Fitness has been an issue all season, off the back of a marathon last campaign, with Ballon d'Or winner Ousmane Dembele making his latest comeback at the weekend after a lay-off with a calf injury.
Key midfielders Fabian Ruiz and Joao Neves have been absent, while Gianluigi Donnarumma has never been adequately replaced in goal.
"We are clearly in difficulty at the moment but we need to maintain hope that will change," said Luis Enrique on Friday. "Confidence is not just something you buy at the supermarket."
Rosenior will be hoping to exploit PSG's weaknesses and repeat the achievements of Roberto Di Matteo and Thomas Tuchel, who both led Chelsea to Champions League glory having been appointed mid-season.