Rafael Camacho, Sheyi Ojo and Adam Lallana - the England midfielder captaining the side - were on target before the break at Prenton Park on Tuesday.
According to a report by Daily Mail, Liverpool were leading 3-0 when Karius kicked a free-kick from 20 yards straight to Tranmere's substitute Johnny Smith.
Speaking after the Tranmere game, the Liverpool manager tried to downplay Karius' mishap against the League Two side.
It was another very bad mistake that seems to suggest Karius is struggling to throw off the psychological scarring he sustained against Real Madrid in the Champions League final at the end of last season.
Wimbledon: Anderson defeats Isner in 6-hour thriller
ESPN commented the match lasted longer than the original Star Wars trilogy at a combined total of 6 hours, 19 minutes. This one seems rather tidy by comparison: Anderson won 7-6 (6), 6-7 (5), 6-7 (9), 6-4, 26-24.
The42 is on Instagram! We can't make a story after each mistake.
Ben Tollitt, who appears to be a Liverpool supporter, could be seen mouthing an insult at Karius after he dropped the clanger.
"I don't like it, he doesn't like it, but it will happen, so let's carry on and make the best of all these situations by learning from them". Our job is to perform and you do what you do and that is part of the deal.
After the pre-season friendly, Klopp was quick to defend his goalkeeper and while I expect nothing less from him, I really hope it's not an indication that Karius will continue between the sticks next season. I would say the second one but we don't talk about that.
"We need to make the most of the situation and learn".