Arsenal boss Mikel Arteta will have to beat one of the most influential figures in his football life when the Gunners face Luis Enrique's Paris Saint-Germain in the Champions League semifinals.
Arteta's side host PSG in the first leg on Tuesday as the Spaniard aims to lead Arsenal to only the second Champions League final appearance in their history.
Standing in his way is a close friend who, along with Manchester City boss Pep Guardiola, played a major role in his compatriot's impressive transition from the pitch to the dug-out.
Luis Enrique was a senior star at Barcelona when Arteta started his playing career at the Camp Nou, a period that had a major impact on his managerial philosophy with Arsenal.
"He was extremely supportive with the young players, he was one of the main characters by far. I have really good memories of him," Arteta said.
"What I love about him is wherever he's been, as a player or a manager, his fingerprints are all over the place.
"You can sense it's his team with the way his players behave, the way they want to attack and dominate games."
The pupil has already got the better of his mentor once this season, when Arsenal eased to a 2-0 win over PSG in the league phase at the Emirates in October.
But PSG have improved dramatically since then, in large part because Luis Enrique's decision to drop Ousmane Dembele against Arsenal for disciplinary reasons has inspired the France forward's superb run of form.
It was the kind of ruthless gamble that Arteta is willing to take himself.
"I admire his honesty. He will look in your eyes and tell you what he thinks. In the end, players appreciate that," Arteta said.
"An unbelievable personality, huge character, huge energy. I learnt a lot of things from him.
"For me he's one of the best coaches in the world and someone who helped me a huge amount. I have the utmost respect both for how he is as a person and his way of working."
The feeling is mutual, with Luis Enrique saying: "He is one of the best coaches at the moment.
"He changed Arsenal's fortunes from a somewhat winless streak to one of the best teams in the world that is competing for titles."
'ELECTRIC ATMOSPHERE'
While Arteta and Luis Enrique are sure to share a private moment together after the tie, they will put their friendship on hold to focus on finally delivering Champions League glory to their clubs.
Arsenal have never won the tournament, losing to Barcelona in the 2006 final, while PSG have a tortured recent history, beaten by Bayern Munich in their only final in 2020.
Securing the European holy grail would make Arteta immortal in north London and banish any questions about his ability to win major trophies.
The Gunners have gone five years without silverware since Arteta won the only prize of his reign in the FA Cup.
Arsenal head into the PSG tie emboldened by their swaggering 5-1 aggregate dismissal of holders Real Madrid in the quarterfinals.
However, they have spluttered in the Premier League, effectively surrendering the title to Liverpool after a series of lacklustre draws.
In Arteta's defence, Arsenal have been hampered by injuries for much of the season, with Kai Havertz and Gabriel Jesus still sidelined.
PSG have already knocked out Liverpool and Aston Villa, setting them up for a hat-trick of English scalps if they get past Arsenal.
In their first Champions League semifinal since losing to Manchester United in 2009, the key for Arsenal could lie in their ability to recreate the fevered atmosphere that swept away Madrid in the last eight.
"With the home crowd behind us, there needs to be an electric atmosphere, and they will push us forward," Arsenal forward Leandro Trossard said.
Trossard could lead the attack against PSG, with makeshift forward Mikel Merino expected to revert to midfield in the absence of the suspended Thomas Partey.
"We want the same as last time. The fans were incredible in the home game against Madrid. If we can do that again it would be amazing," Trossard said.