Marcelo has warned Real Madrid to learn from their mistakes following their 2-1 defeat to Valencia on Wednesday.
Simone Zaza and Fabian Orellana scored inside the first nine minutes at Mestalla, and although Cristiano Ronaldo halved the deficit, the visitors could not prevent a second LaLiga loss of the season.
Zinedine Zidane's side have now suffered three defeats this year - one more than they managed in the whole of 2016 - and remain only a point above Barcelona at the top of the table, although they have a game in hand.
Marcelo believes they had only themselves to blame for the result and has called on his team-mates to prevent a similar slip-up between now and the end of the season.
"I think we started badly, there are no excuses," he said afterwards. "We're to blame, we played badly.
"We tried at the end but we conceded two silly goals and we made mistakes. We're still at the top of the table but we can't start games like that.
"Valencia are a great team, they've been through bad times but it's difficult to play here, the fans get on top of you. We'll learn from these mistakes so it doesn't happen again.
"We've done everything to get the equaliser, but we have to change a few things."