Atletico Madrid host Barcelona on Saturday in the first showdown of the season between two of LaLiga's real title contenders.
The Catalans have won all seven of their opening matches and already have a five-point lead over second-placed Sevilla, placing them firmly in the driving seat in the title race.
Atletico, along with Barca and Valencia, are unbeaten in the top flight but will be nine points behind them if that run without defeat comes to an end at the Wanda Metropolitano.
This match has been a fascinating fixture since Diego Simeone took charge but he has a remarkably poor record in it, despite the success he has brought to the capital club since taking over in 2011.
But could this be his chance to turn the tide, now that Ernesto Valverde is in the opposite dugout? Using Opta data, we take a look...
SIMEONE V BARCELONA MAKES FOR MISERABLE READING
Simeone is rightly praised for upsetting the apple cart at the top of LaLiga but, when it comes to his head-to-head against Barca, there is a lot to be desired.
In 21 matches in all competitions against the Catalans, Simeone's Atletico have only won twice. Both of those wins have come in the Champions League, in 2013-14 and 2015-16.
They have lost 12 of those meetings in total, eight of which have been in LaLiga. They have only taken three points from 11 games in the top flight.
Atleti do, at least, boast an unbeaten record in Supercopa de Espana meetings, although it's a hollow achievement: 1-1 and 0-0 draws in 2013 saw them lose the trophy to Barca on away goals.
2 - Simeone has just won two of his 21 games as manager against Barcelona in all competitions (D7 L12), none of them in . Chance October 12, 2017
WHY DO THEY STRUGGLE?
Put simply, Atleti just do not score enough goals against Barca. They have managed 19 in 21 meetings during Simeone's time in charge but just nine in their 11 in LaLiga.
They have conceded 31 goals in total in that time, 20 of which have come in the top flight, giving Barca an average of close to two goals per game.
Their combative approach in key games is often heralded as a key part of Simeone's success, but it has not helped them against Barca. They have conceded 393 fouls against Barca, compared to just 231 given in their favour, meaning they have effectively scored one goal for every 21 fouls committed.
They create few chances, too: they have managed just 74 in their 11 LaLiga meetings, which is only 14 more than their tally for their first seven matches of this season.
Their possession figure is also extremely low, averaging at 31 per cent in the league, although that has rarely stopped them achieving results. For instance, they have won two of four Champions League meetings when only managing 26 per cent of the ball.
28 -Since Koke joined against Barcelona (at Sep 2009), Koke is the player with most assist at set play in .Draftsman October 12, 2017
VALVERDE ERA COULD HERALD A CHANGE
The data does not bode well for Atleti but one thing that could give Simeone some impetus is the man in the opposition dugout.
Ernesto Valverde has been involved in nine LaLiga matches against the Argentine as head coach of Valencia and Athletic Bilbao. He has yet to taste victory.
While taking Barca to the capital might not be quite as daunting a prospect, there is no doubt this is Valverde's sternest test since taking over from Luis Enrique, perhaps with the exception of their home Champions League clash against Juventus.
When you consider Atleti have averaged 1.7 goals per game and less than 0.6 conceded in the league this season, the signs are there of an end to Barca's dominance over Simeone.
