Los Boquerones have endured a run of three straight defeats, conceding eight goals without scoring any in the process.
The most recent reverse was Saturday's humiliating 5-0 home defeat at the hands of Celta Vigo, which dropped them to 16th in the table.
Manager Bernd Schuster was not shy in letting his players know exactly what he thought of their abject performance.
His players have vowed to put things right, but Portillo knows it is actions on the pitch which will count the most at El Prat as Espanyol celebrate their 113th anniversary.
He said: "It is logical that the coach is angry, as are all the staff.
"We have to endure the criticism and keep our heads up. We are not the team we were before and we must work to overcome this situation.
"It is very difficult to digest this result. There was little talk and a lot of work after it
"We have not been good in the last few games and we should talk less and work harder."
Espanyol, meanwhile, are eighth in La Liga despite their 3-0 defeat to Levante.
But manager Javier Aguirre will be without Javi Lopez once again as the midfielder continues to recover from a leg injury, while Hector Moreno is a doubt after suffering a quadricep injury at the weekend.