Liverpool manager Jurgen Klopp insists there is still plenty of hard work despite a comfortable lead in the Premier League and qualification for the last 16 of the Champions League being secured.

A header from former Red Bull Salzburg midfielder Naby Keita and a brilliant, impossible-angle finish from Mohamed Salah clinched a 2-0 victory in Austria and ensured they finished top of Group E.

The match, from which they needed a minimum of a point to qualify, was far from straightforward in the first half, but a professional performance.

And Klopp knows more will be required if they are to go further in defence of their European crown while also maintaining the quest for a first title in 30 years.

"Of course there are limits. We have to work hard to achieve what we want," he said.

"We wanted to move on to the knockout stage, that was important.

"It wasn't our plan to be leader in the Premier League in December but it's great to be there, but we need to use everything and work very hard.

"There are limits, but if the boys play like that it makes it easier for us. But they have to be ready and try to achieve their goals like they did (against Salzburg)."

The one downside to the performance was defender Dejan Lovren being forced off for the second successive match with a hamstring problem.

However, the manager is hopeful it is only a recurrence of the cramp he suffered at Bournemouth on Saturday – especially as fellow centre-back Joel Matip appears to still be a couple of weeks away from recovering from a knee injury which has sidelined him for 12 matches.

"We hope it's exactly the same like last time he felt something and we made a decision," said the manager.

"It wasn't cool. He played really well and was very important in those 55 minutes.

"We don't know at the moment. Like last time, we have to see."

Salah's goal was his 20th in the Champions League and he is only the second player to reach that number in Europe's elite competition, Steven Gerrard (30) being the first.

The goal was brilliant, fired in from the narrowest of angles with his weaker right foot, but what made it more remarkable was that he missed a hat-trick of far simpler chances up to that point.

Just over a minute after Keita had put them ahead Salah slid home a curling shot which virtually brushed the near post before creeping inside the far upright.

Asked to explain the goal Klopp said: "Thank God I don't have to. It was for sure the most difficult situation he had tonight.

"He played really well but didn't score in the situations we expect him to score. Staying on track and making such a decisive but a difficult finish says probably much more about him than all the other goals he scored.

"He stayed concentrated, believed in the next moment and it was a very good goal. A sensational finish."