Xabi Alonso's perfect start as Real Madrid manager will be tested when his side visit a vengeful Atletico Madrid on Saturday, with Diego Simeone's team still seething over a controversial penalty decision that cost them a Champions League quarterfinal spot.
Real Madrid arrive at the Metropolitano stadium with a flawless record of six wins in LaLiga, sitting five points clear of second placed Barcelona and nine points ahead of Atletico.
Atletico are motivated by more than just local bragging rights – they remain furious over Julian Alvarez's disallowed penalty in last season's round of 16 Champions League defeat.
The incident, where Alvarez's penalty in the shootout was disallowed by VAR due to a controversial "double touch" decision after he slipped while attempting the shot, allowed Real Madrid to progress into the last eight.
The controversy was so significant that the International Football Association Board (IFAB) later updated the rulebook, clarifying that the rule was meant to prevent deliberate double touches, not punish accidental slips.
Several months on, the Atletico manager is still furious about the incident which he believes robbed his side of victory.
"We feel outraged, violated... It wasn't just another penalty, it was a penalty that would have sent us through to the quarterfinals... I'm angry, honestly angry," he told DAZN recently.
That defeat extended Atletico's trophy drought to four consecutive seasons and left Simeone under unprecedented pressure as he entered his 14th season as the club's manager.
Things got worse as they had a dismal start to the season, with just one win in their first six matches in all competitions despite sky-high expectations following the club's massive summer investment.
But after they were left licking their wounds when they suffered a last-gasp defeat to Liverpool at Anfield in their Champions League opener last week, they managed to recover with a thrilling 3-2 comeback win against Rayo Vallecano in LaLiga on Wednesday, giving them a boost ahead of Saturday’s derby.
Despite the win, Atletico find themselves languishing in eighth place in the LaLiga standings after six games, a far cry from their lofty ambitions.
In contrast they will be up against a Real Madrid team who have bagged 18 points so far this season in a perfect start with Kylian Mbappe shining with seven goals atop the LaLiga scoring race.
Saturday's derby promises to be a clash between Alonso seeking validation for his project and Simeone's side desperate for vindication against their old, bitter rivals.