For a second straight season, Atletico Madrid have been ousted by a third-tier opponent in the Copa del Rey.
The La Liga leaders lost 1-0 at Barcelona-based club Cornella in the round of 32 on Wednesday after a toothless performance.
Cornella defender Adrian Jimenez scored the game's only goal in the eighth minute from a cross by Agus Medina at the near post.
Last season, Atletico lost 2-1 to third-tier team Cultural Leonesa in the cup competition.
Coach Diego Simeone acknowledged that "it is the second year in a row" that his team has flopped against a team with a fraction of the budget his club enjoys.
"Our rivals have played better," Simeone said.
"We had some good attacking moves, but overall our rival (Cornella) always played better.
"They took advantage of the set piece and got their goal.
"It was even more uphill after the sending off. Now we have to find solutions."
Atletico were never comfortable on Cornella's artificial turf and the closest they came to equalising was when Saul Niguez's shot hit the woodwork midway through the first half.
They had to play with 10 men from the 65th minute in Wednesday's tie after Ricardo Sanchez received his second booking.
To compound their woe, Atletico also lost centre-back Jose Gimenez after he injured his left ankle early on while Joao Felix also left the match in the second half after he hurt an ankle.
Cornella coach Guillermo Fernandez told Simeone he "was sorry" for the result.
"I said what I felt," Fernandez said after the match.
"For these clubs, which are under so much pressure, these matches are very uncomfortable.
"For us today is a special day."
Atletico are not alone in getting caught off-guard. Third-tier sides ousted top-flight teams Celta Vigo and Getafe on Tuesday.
In action on Wednesday, top-flight clubs Granada, Real Betis, Alaves and Osasuna won to reach the last 16 while others to advance were Espanyol, Malaga, Leganes, Rayo Vallecano, Fuenlabrada and third-tier Navalcarnero.