Jose Mourinho is rarely one to praise his rivals, least of all Liverpool, so the fact that Jurgen Klopp brought some positivity out of the Portuguese is notable.
Mourinho had plenty of run-ins with the Reds during his two stints as Chelsea manager. He was linked with the job before Rafa Benitez's appointment, and the 2005 'ghost goal' incident was one of many run-ins between the two clubs in the first few years of the century.
Nearly a decade later, with Brendan Rodgers in the Liverpool dugout, Mourinho's Chelsea dealt the Anfield side a devastating blow in their title chase. In 2019, though, Rodgers' successor Jurgen Klopp won his counterpart around.
Mourinho's relationship with Liverpool was a troubled one during his spells with Chelsea and Manchester United. The 2005 meeting was just one of many clashes with Benitez in Europe, with Liverpool also coming out on top in the 2007 semi-finals following a penalty shoot-out.
The rivalry between Liverpool and Man Utd, meanwhile, didn't need Mourinho to invigorate it. There was room for more drama, though, with Mourinho and Klopp notably clashing during a 2017 draw.
"[Klopp] thought I was asking for his player to be sent off," Mourinho said after the Old Trafford draw. "I wasn’t. There was no problem at all. I think the game was correct."
Klopp, however, contested his opposite number's stance on an incident involving Roberto Firmino. “He [Mourinho] wanted the minimum of a yellow card, I don’t know," he said.
"I think the ref whistled before anything else happened. Roberto is a footballer from head to toe and he wanted to stay in the game. He could have passed the ball but that was a yellow card for Herrera and nothing else."
Back in the 2018-19 season, Mourinho saw his Man Utd tenure cut short after a December defeat at Anfield. Months later, though, it was another Liverpool win which caught the eye.
Klopp's team were playing catch-up in the title race by the time they faced Barcelona in the Champions League semi-finals. A 3-0 defeat at Camp Nou meant it looked all but over for the English side, but a rousing comeback in the second leg saw them follow Roma in stunning the Catalan side and overturning a three-goal deficit.
Xherdan Shaqiri impressed in both games, scoring twice against United and setting up the goal which brought his team level on aggregate in Europe. However, as Mourinho saw it, Klopp was very much the man of the hour.
No longer constrained by direct rivalry, Mourinho felt able to speak openly about Klopp in May 2019. And the former Dortmund boss had seemingly done enough to make Mourinho's spiky relationship with Liverpool a thing of the past.
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"For me, this [comeback] has one name - Jurgen. This is about him," Mourinho told Sky Sports after Liverpool's win. At the time, he was between jobs - he would join Tottenham later in 2019 - and was full of praise for the Reds boss.
"This is a reflection of his personality don't give up his fighting spirit, every player giving everything. He's not crying because he's missing [injured] players, he's not crying because they're playing 50 or 60 matches a season.
"Today is about Jurgen's mentality. This is not about tactics, not about philosophy. This is about heart and soul and fantastic empathy he has created with that group of players."
Klopp and Mourinho have been in opposite dugouts on plenty of occasions since then, though not in Europe. Mourinho took over at Spurs when they were fresh off a Champions League final defeat to Liverpool, but his only campaign in that competition ended at the hands of RB Leipzig in 2020.
In two seasons with Roma, he has won the Europa Conference League and reached the final of the Europa League. The Giallorossi will take part in the latter next term, where they could end up facing Liverpool after the Reds' fifth-place Premier League finish.
A reunion is far from certain, though. Mourinho has attracted the attention of Paris Saint-Germain, and has yet to make a decision on his future.
“I can’t say I will be here next season,” Mourinho told reporters after Roma lost the Europa League final to Sevilla. “I will go on holiday on Monday, then we will speak.
"I told the owners I will tell them if I start talks with another club. As of now no other club called me. It is time for me to talk to the owners. It is time for the owners to talk to me.”
