Real Madrid coach Carlo Ancelotti urged the club's fans to "be positive" after captain and goalkeeper Iker Casillas was again targeted with whistles in Tuesday's 5-1 Champions League drubbing of FC Basel.
Casillas, who celebrated 15 years since his Real debut on Friday, was blamed by some supporters for not doing more to prevent Atletico Madrid's opening goal in Saturday's 2-1 La Liga defeat at the Bernabeu.
While one section of the crowd whistled the Spain stopper every time he touched the ball on Tuesday, others tried to drown the protests out with applause and the fans appear to be divided over whether Ancelotti should stick with Casillas or promote new signing Keylor Navas.
Casillas could do little to prevent Basel's goal, a precise low shot by Derlis Gonzalez, but he did pull off a brilliant save from the lively Gonzalez later in the game that earned a rousing ovation.
Ancelotti has refused to be drawn into a public debate about the keeper's position and told Spanish television broadcaster Canal Plus he wanted an upbeat attitude from the fans.
"We have to be positive," said the Italian, who led Real to a 10th European crown in his first season in charge in 2013-14.
"I don't listen to the whistling. If the fans sing 'How could I not love you?' then I do hear that because I want to be positive in life."
Real's performance in the first match of their title defence was the ideal tonic after two straight La Liga defeats left the club mired in 13th place and already six points behind leaders and arch rivals Barcelona.
Ancelotti, who has noted that Real also started last season poorly before winning a record-extending 10th European crown and the King's Cup, said he was pleased with the players' intensity against Basel.
"It's clear that not everything has been solved but I liked the reaction of the team," he told a news conference.
"It's normal that people get nervous if you lose two games at the start of the season."
Real's next outing is a La Liga game at promoted Deportivo La Coruna on Saturday.