Barca lost the first-leg of their Copa del Rey round 16 tie 2-1 at Levante.
"It's a bittersweet night," Murillo said after the match. "The result is not the best.
"We have to take advantage of Coutinho's goal at home."
Murillo is continuing to integrate into the team and is listening closely to what Ernesto Valverde wants from him.
"I've tried to fit into the group," he said. "I'm taking things positively.
"The coach keeps asking me to work."