Ekitike struck the winner on 85 minutes, but was sent-off after being shown a second yellow card for taking off his shirt and showing it to Liverpool fans.
The France international had been booked earlier in the game and despite knowing he would be shown a second yellow card, Ekitike still celebrated as he did.
Afterwards, Slot snapped: "What were your two words? That was ‘needless’, yes. And it was ‘stupid’. Yeah, it was. The first one was already needless and to a certain extent stupid, because you have to control your emotions. I know how hard it is if you play Premier League or every league in the world, if you are a No.9 then the defender can almost do everything he wants, and then when you shirt-pull a little bit or you push him a little bit then you get a free-kick against you.
"But it’s always the best to control your emotions, and if you cannot control your emotions do it in a way that doesn’t lead to a yellow card. I think I said when I got my red card against Everton (last season), that is always stupid because you can show your emotions but if it leads to a yellow or a red card then it’s stupid. And that’s what happened in the first yellow.
"I told him as well and I said it to numerous media already, if you score in a Champions League final in the 87th minute after outplaying three players and hitting it in the top corner, I can maybe understand that you’re like, ‘This is all about me, what did I do?’ But I am old fashioned, I’m 47 and old maybe. I haven’t played at this level but I did score a few goals and if I would have scored a goal like this, I would have turned around and walked up to, in this situation, Federico Chiesa and said, ‘This goal is all about you, this is not about me.’ So, yeah, needless, not smart. You call it stupid. I call it stupid, by the way, as well."
Apology
Meanwhile, Ekitike took to social media to apologise for his dismissal on the night. He will be suspended for Liverpool's Premier League clash with Crystal Palace.
He posted: “I was so excited tonight to help the team achieve another victory here in our home for my first Carabao Cup match.
“The emotion got the better of me tonight. My apologies to all the Red family.
“Thanks to the fans who always support us and to my teammates for securing this victory.”