Mignolet, who captained Liverpool for the match, brought down the forward late in the first half, but despite the Potters' protestations that he denied them a clear goalscoring opportunity, Atkinson only booked the goalkeeper.
Per Sky Sports' Gerard Brand, Reds boss Klopp said:
"I don't think [it was a red]. I was pretty sure in that moment that it was a yellow card. It was outside of the 18-yard box, and I saw two players in our shirt in a better position than the goalscorer, that's how it looked for me.
"I don't think that it looked like that for any of the Stoke fans. There were two Liverpool players weren't there? I can really imagine that for Stoke supporters and for Mark Hughes they see it differently, but if you really look at it, it's a yellow card."
Klopp's assessment of what Stoke manager Hughes' take on the incident would be proved accurate, as the Welshman described it as the "key moment in the game" and was incredulous the officials did not agree it was a clear goalscoring opportunity, per BBC Sport's Mike Henson.
Stoke's official Twitter account picked up on the incident immediately:
Joel Matip and Joe Gomez were alongside Diouf as he bore down on goal, but they weren't goal-side of him—had he managed to round Mignolet without being fouled, it's unclear whether they would have been able to cover before Diouf got a shot away.
Former Everton star Phil Neville believes the Belgian should have received his marching orders:
Liverpool led from Sadio Mane's 17th-minute strike before a six-minute brace off the bench from Mohamed Salah—a well-taken volley and a cool finish after a run on goal—sealed the victory.
"Thank God for Salah," Klopp exclaimed after the match, per Steve Bates, writing for the Mirror.
Per Brand, Klopp added: "The first [Salah goal] looked like it was the easiest thing in the world to make the volley. It's not as easy as it looks! It helped a lot. I'm pleased for him, pleased for the team. I think we deserved these three points."
The 25-year-old has scored 17 goals and recorded four assists in all competitions this season after arriving in the summer, and he set a new record on Wednesday:
Bleacher Report's Karl Matchett noted Salah's effect on opposition defences:
The forward has been the signing of the summer and a tremendous addition to the Reds attack, having taken his game—and his goalscoring—to another level since arriving at Anfield.
For all his effort, the Reds are only fifth in the Premier League, though. They will need to keep on winning if they are to break into the top four and stay there.