They travel to in-form Rayo Vallecano on Wednesday and Koeman says his side “cannot afford back-to-back losses”.
“I’m a grown up and I know how these things work,” Koeman said on Tuesday.
“I want to enjoy the time that I have left, if it is eight years, six months, one year, or some weeks. I think it’s important that we win this game in Madrid, we cannot afford back-to-back losses.”
Falcao a hero once more in Madrid
Following the defeat on Sunday, Koeman’s car was surrounded by some Barcelona supporters, who he has since dismissed as “uneducated people”.
He added: “It is a social problem. Uneducated people that don’t understand rules and values.
“Inside the stadium the environment was completely different and that is what I keep in mind, that festive vibe, not with those kinds of people.”
Rayo are seventh in La Liga, one point ahead of Barca, having been inspired this season by the arrival of veteran Colombia striker Radamel Falcao.
They have won four of their last six games and will be roared on by an expectant home crowd, while Barca may be without teenage forward Ansu Fati because of pain in the knee he had surgery on.
“They are a really tough team to beat and they are even better this season,” said Koeman. “We’ll have to be in our best shape to beat them in their home.
“He [Fati] doesn’t feel right, we will decide on Wednesday morning if he makes the trip.”