The Dutchman shook off a fever to score on the day.
Klopp revealed, "Last night, Gini was not in the team hotel because he had pretty much everything you don't want to have the night or two nights before a game. That's the news you get in the morning before the last session of the week. Then, after another couple of hours' sleep he said he felt really good and he thought he could play.
"But the doc said he is still infectious, so stay away. So I was only concerned today when he scored a goal and everybody gave him a hug, to be honest! I've said it a few times and it's always difficult to talk about that – because people think about why I have to mention it – but these players, the character and mentality of these boys, is the only reason why we are where we are."