The club's record signing was sent for an early bath for headbutting Joachim Andersen during the 1-1 draw.
And as Nunez made the lonely walk off the Anfield pitch, only one person in history knew exactly what he was going through - Joe Cole.
That's because 12 years ago, eerily on the exact same day as Nunez on August 15, Cole was red carded in Liverpool's first match of the 2010/11 season.
The ex-England international was dismissed in first-half injury time of Liverpool's 1-1 draw with Arsenal for a lunge on Laurent Koscielny.
As was the case with Nunez, the Reds managed to rally and score with ten-men as David Ngog opened the scoring.
A stoppage-time own goal from Pepe Reina hauled Arsenal level minutes before Koscielny, who was also making his Premier League debut at Anfield, ensured both sides finished with 10 men.
Speaking after the match, then-Liverpool boss Roy Hodgson said of Cole: "He was devastated at half-time.
"It was his debut, the atmosphere was fantastic and he was desperate to do well.
"He was not playing at the top of his game, but was trying hard to get to that level, when suddenly he gets sent off.
"He was saddened by it all and not least because it put us in a difficult situation."
Unfortunately for Cole, the early red card proved to be a sign of things to come in what his only full season at Liverpool.
He managed just two Premier League goals for the rest of the campaign before he was shunted out to Lille on loan the next summer.
Nunez will have to avoid following the same trend after Klopp suggested this was an out of character outburst from his new man.
"I haven't said anything to him yet… when I saw it I of course saw that it was a red card," Klopp told talkSPORT afterwards.
"We cannot change that and he cannot behave like that.
"He's a good boy but did something not so good. We will talk to him and he will learn from that and we will carry on."