Madrid - Real Madrid boss Zinedine Zidane admitted he is concerned by his side's form after squeezing past Las Palmas 2-1 on Sunday thanks to Casemiro's injury-time winner.
Zidane's men were outplayed by Las Palmas for large spells on their first visit to the Canary Islands in 15 years, but made the hosts pay for poor marking at set-pieces as Sergio Ramos and Casemiro both netted from corners.
"I go away happy with the result, but a little worried with what I saw in the second-half," said Zidane.
Victory closed the gap on La Liga leaders Barcelona to 12 points, but with only nine games to play, Madrid's remaining realistic hope of a trophy this season is the Champions League.
The 10-time European champions progressed to the quarter-finals with a similarly unconvincing display to see off Roma in midweek, but Zidane insisted his side's standards must improve dramatically if they are to go further in the Champions League.
"We aren't thinking about the Champions League. The players were thinking about what they had to do in the game today, but the truth is we gave away the ball an incredible number of times," he said.
"If we want to aspire to something in the future, we have to play better. That is clear because playing like this we won't go anywhere."
Madrid were bailed out on a number of occasions by goalkeeper Keylor Navas, but Willian Jose looked to have finally handed Las Palmas a share of the spoils when he cancelled out Ramos's first-half header three minutes from time.
However, Casemiro popped up unmarked to head home in stoppage time before Ramos saw his 20th red card as a Madrid player for a second bookable offence.
Both Ramos and central defensive partner Pepe will now be suspended for the visit of Sevilla next weekend.
"I don't think football is unjust because we scored from two set-pieces and that is part of football too," added Zidane.
"Las Palmas did very well and caused us a lot of problems, but it is our contribution that bothers me."