Karius feels he's now Liverpool's outright No1: "To be a proper established goalkeeper takes a few seasons. I need to pay back the confidence from the manager. I am still young but I need to keep working hard.
"Our focus is on Saturday now [against Manchester United]. It is a very, very big game and then we will look forward to our opponents in the quarter-finals."
Meanwhile, captain Jordan Henderson said: "We are through to the next round which is the most important thing - obviously we wanted to win - but we have to give credit to Porto because they played well.
"This is the business end of the season. The next few months are very important for the team. We need to put performances in like we have been and the results will follow.
"We couldn't manage to break them down tonight but there's a big game this weekend which we need to be ready for.
"I got a dead leg at the end but I will be fine."