Real Madrid coach Jose Mourinho will renew one of football's most bitter rivalries on Sunday when he takes charge of his first Clasico since returning to the club, with La Liga leaders Barcelona awaiting him at Camp Nou.
The Portuguese veteran's first spell at Madrid was defined in large part by his battle to end Barca's dominance under Pep Guardiola, with relations between the Spanish giants slumping to their lowest ebb.
Mourinho managed to break Barca's spell by guiding Real Madrid to the Spanish title in 2012, the crowning achievement of his reign from 2010-13.
Clasicos became increasingly compelling during that period, some would say not for the right reasons, as he and his staff clashed with their Barcelona counterparts both pitch-side and verbally in the media.
The 63-year-old worked as an assistant at Barca under Bobby Robson and Louis van Gaal in the 1990s but was overlooked for Guardiola in 2008 when the Catalans replaced Frank Rijkaard.
Mourinho's frequent battles with Guardiola, Lionel Messi and even with Madrid's own icons like Iker Casillas sometimes overshadowed his sporting achievements.
The most infamous flashpoint came in August 2011, when Mourinho poked then Barca assistant coach Tito Vilanova in the eye.
Earlier that year, at the end of the prior season, Madrid and Barca clashed four times in just 18 days, illustrating the intensity of the rivalry.
The first was in La Liga, a 1-1 draw, which helped Barcelona take a step towards retaining the Spanish title as Madrid trailed them.
Mourinho's Madrid beat Barca to win the Copa del Rey in the second, with Cristiano Ronaldo scoring the winner in extra time.
Then the Catalans got the better of Los Blancos in a Champions League semifinal double-header, winning the first leg 2-0 at the Santiago Bernabeu, with Madrid defender Pepe sent off. Mourinho called it a "scandal".
Barcelona held Real Madrid to a 1-1 draw in the second leg to reach the final, which they went on to win.
It was in this period that Guardiola said he could not and would not compete with the "boss" Mourinho in the press room.
STOPPING FLICK'S BARCA
Mourinho has hit the ground running in his second spell at Madrid in that regard.
The coach brandished print-outs of incidents after losing the derby clash to try and prove his point that Atletico Madrid deserved two red cards, and refused to attend a press conference after Vinicius Junior was sent off against Villarreal.
Many believe Mourinho employs these tactics as a distraction to take the pressure off his team when they are not performing.
A victory in the Clasico might encourage him to focus on the football, and stopping Hansi Flick's side - back-to-back Spanish champions - is one of the main reasons he was rehired by president Florentino Perez.
Flick's Barca have won six of seven Clasicos against Real Madrid since the German arrived, scoring 22 goals and shipping only 11.
Mourinho insists it is impossible for his team to be at the level he wants them to be at after such a short time in charge.
"I've been here for over a hundred days. Obviously, we are not where I want, but there are things we are doing better today than before," said the coach.
Madrid have won their last four matches between La Liga and the Champions League, and after sharing minutes around early in the season, some preferences are emerging.
Although Mourinho said initially he did not see midfielder Federico Valverde as a right-back, where he has been used in the past, he has selected the Uruguayan there in the last two games, ahead of Denzel Dumfries and Trent Alexander-Arnold.
"We created a lot on that side, and Fede had a fantastic match," said Mourinho after the Leipzig win.
In Valverde's place in midfield, Mourinho deployed Arda Guler against Sevilla on Sunday and then Bernardo Silva against the German side, with Madrid improving on the ball and retaining more possession.
However, the Clasico poses a different challenge. Mourinho, who deployed defender Pepe in midfield against Barca, may revert to type to try and spoil the hosts' flowing football.