Felix was named on the bench for Atletico's first game of the season which saw them take on Granada on Monday.
Diego Simeone's men would go on to win 3-1 through goals from Alvaro Morata, Memphis Depay and Marcos Llorente.
But during the match certain sections of the Wanda Metropolitano were keen to let Felix know how they felt about him.
As the forward warmed up before the match got underway, chants could be heard from the crowd that sang: "That Portuguese, what a son of a b**** he is!"
Felix is not in Atletico's good books after declaring that he would love to play for their league rivals Barcelona.
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"Barcelona has always been my first choice and I'd love to join Barca," he said last month.
"It was always my dream since I was a kid. … If it happens, it will be a dream come true for me."
The Portugal international is not fancied by Simeone having been loaned to Chelsea midway through the season last term.
In 20 appearances for the Blues, he scored four times and provided no assists, receiving a red card on his debut against Fulham as well.
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New boss Mauricio Pochettino did not want to make the transfer permanent and Felix has since returned to Atletico, where the situation is growing more and more toxic.
The 23-year-old's revelation that he wants to join Barcelona has certainly not helped.
And the Blaugrana might not even be able to afford the attacker, who cost Atletico £120million in 2019.
A swap deal with Ansu Fati has been mooted but talks have not progressed over the summer while Saudi Arabia could be Felix's last chance to leave Madrid.
The former Benfica ace was once tipped to take over as Cristiano Ronaldo's successor for Portugal but that has failed to live up to expectation.
There remains huge pressure on Atletico to make something of their record purchase.
Simeone, who Felix has had reported bust-ups with, spoke out on the situation after leaving the youngster on the bench against Granada.
"I see that the LaLiga has started, he is with us, he knows what we need and want, what we are going to demand of him," the Argentine coach told AS after Monday's result.
"He has to compete with Memphis, Griezmann, Morata and Correa and if he is better than them, he will play."