The rivalry between Roma coach Jose Mourinho and his Real Betis counterpart Manuel Pellegrini has simmered down over recent years, but Thursday night's clash in the Europa League is a potential flashpoint.
It's a match where the Italian side are fighting to keep their footing in the competition, while Betis can potentially wrap up qualification with a win at Seville's Benito Villamarin Stadium, where they have excelled this season.
Mourinho was appointed as Real Madrid coach in 2010 after presidentFlorentino Perez sacked Pellegrini, controversially, after he secured a then club record total of 96 points in La Liga. It just wasn't enough to beat Pep Guardiola's Barcelona, who finished on 99.
"If Madrid get rid of me I won't be going to coach Malaga, I'll be at a top level side in Italy or England," scorned Mourinho, when asked what he would do if ousted by Perez.
Malaga was Pellegrini's new home, helping them to fourth place and a new club record of 58 points. In the Champions League the following season they reached the quarter-finals, where Borussia Dortmund beat them in a thrilling quarter-final tie.
On the pitch, Madrid unsurprisingly bested Pellegrini's Malaga whenever they met, once with a thumping 7-0 victory, and Mourinho lifted La Liga in 2012, something his rival did not manage.
The pair clashed again in the Premier League, with the Portuguese back in charge of Chelsea after a triumphant stint at Inter Milan, and the Chilean at the helm of Manchester City.
Pellegrini refused to shake Mourinho's hand after Chelsea beat City 2-1 in 2014, but he had the last laugh as City won the title.
Mourinho has the edge historically, with eight wins out of 16 confrontations, and three draws, although when the sides met in Italy last week, Betis emerged with a 2-1 win.
Pellegrini, an engineering graduate, has always leaned towards entertaining football and he has been able to infuse that into Betis' game, without sacrificing results.
From hitman Borja Iglesias to legendary winger Joaquin and exciting playmakers Nabil Fekir and Sergio Canales, the Andalusian side are easy on the eye.
They won the club's fourth major trophy and first since 2015 last season, lifting the Copa del Rey. It was Pellegrini's first trophy since the 2016 League Cup in England.
"Mourinho has had a brilliant career and he went for the mature option going to Roma," said Pellegrini. "I remember when I went to Malaga after Madrid, he said he would never coach a team like Malaga.
"I was proud of having gone there because I like a challenge, and that was a new project … I think the same happened to Mourinho.
"He was in the football elite and now he likes a challenge too, like taking Roma to the Champions League or winning the Conference League."
While the pair may have buried the hatchet, a lot is on the line on Thursday night. Betis, with victory, would be a lot closer to progressing as group winners, which would save them a tricky tie with a side that drops out of the Champions League.
Mourinho needs one more victory in Europe to earn his 107th win in continental competition, a figure that would see him overtake former Manchester United manager Alex Ferguson as the all-time record holder.
It is a statistic which ties together his former successes, at football's peak, along with his new path at Roma, one which Pellegrini considers just as worthy. However, he isn't planning on letting his old rival achieve it in Seville this week.