BBVA Primera Liga leaders Real Madrid face their biggest test of the season to date when they travel to play Celta Vigo on Saturday afternoon.
The game will also be a major test for Celta, who have so far been the surprise package in Spain this season and who kick off the game level on 18 points with Real Madrid and looking to show their positive start is no flash in the pan.
Real Madrid travel to the north-west of Spain after a hard-fought 0-0 draw away to Paris Saint Germain in the Champions League in which Rafael Benitez' s side showed their new-found defensive toughness.
Benitez has been criticized for what some see as an overly defensive attitude in charge of Real Madrid, but the fact is that last season the side lost the league title as the result of some poor defensive displays and this season they have been a lot tougher to unlock at the back.
They will need to maintain that toughness against an exciting Celta side, who have been scoring goals almost at will and who have already beaten Barcelona 4-1 in their Balaidos Stadium this season.
The attacking trio of Nolito, Fabio Orellana and Iago Aspes has no need to envy the talent of any attack in Spain and they have the pace to make Madrid suffer as they showed against Barca and in last weekend' s 2-1 win away to Villarreal.
Add to that a packed house in Balaidos and it promises to be a tough afternoon for Benitez's men, although a win would go a long way to showing Real Madrid's title credentials and silencing critics.
Benitez has some injury worries with Mateo Kovacic joining the walking wounded and with Gareth Bale, Dani Carvajal and James Rodriguez definitely out and Karim Benzema and Sergio Ramos both doubts for the game.
The Madrid coach is likely to keep faith in hard-tacking Casimiro in central midfield, while Isco and Lucas Vazquez stand by to replace Bale and Benzema.
On Saturday, fans will know how real both sides' title aspirations really are.