Atletico Madrid's La Liga title challenge has been floundering for a while and if they lose at home to Barcelona on Sunday, it could be over before it really began.
Barca sit three points ahead of Atletico in the table and have a game in hand to come against Real Madrid, after their match in October was postponed until December 18.
It means defeat for Atleti this weekend would give their opponents a six-point advantage, with the possibility of either Real Madrid or Barcelona extending that to nine with a victory in next month's Clasico.
That would be a formidable gap to close, particularly given Diego Simeone's side have to play away at the top two in the second half of the season, limiting their ability to cut any deficit in head-to-heads.
There has also been little so far to suggest they could put together a consistent run of results.
In their 1-0 defeat to Juventus on Tuesday, Atletico failed to convert from 15 shots, which according to Opta is their second highest in any Champions League away game for 16 seasons.
"We are experts in patience and hard work," said Simeone afterwards. "At some point we will have a great match and score lots of goals.
"We are a strong team with a strong block and in attack we are generating better chances. But we are not ruthless enough and when you're not ruthless, the rest is of little use."
"Players who are good always understand each other and with time they understand each other more."
"Now he has a special feeling for the game against Atletico."