Liverpool captain Jordan Henderson says his side still have to work to do if they are to qualify for the last eight of the Europa League.
The Reds took firm control of their last-16 tie with Manchester United with a deserved 2-0 first-leg victory on Thursday.
Goals from Daniel Sturridge and Roberto Firmino either side of half time helped the home side win the first European meeting between the sides.
However, Henderson has warned his teammates against complacency, despite the comfortable manner of victory at Anfield.
"It is only half the job done. Anything can happen in football and I have seen stranger things happen," said the midfielder. "It is only half-time so we have to make sure in the second half at Old Trafford we play like that again because it will be very difficult.
"It was a good team performance. You have to concentrate on performances and I feel in the last few weeks performances have been good and results follow. We have built some momentum and confidence and hopefully we can continue that until the end of the season. This gives us another boost."
Henderson impressed alongside Emre Can at the heart of Liverpool's midfield but was forced to tread carefully after receiving a second-minute booking from Spanish referee Carlos Carballo.
Jurgen Klopp had previously warned his players about Carballo, who had handed out 74 yellow cards and six reds in his previous 12 games.
"I was a little bit concerned getting a yellow card after two minutes," admits Henderson. "I didn't think it was a booking but maybe a foul as my studs were showing but I got the ball.
"I just needed to be careful and not make any silly fouls as I could easily have been sent off but I felt I managed myself well."
Carballo also booked Alberto Moreno and Dejan Lovren, who now run the risk of a suspension should they be carded in the return leg at United next week.
The Spaniard handed out six bookings, three to each side, causing Klopp to question the official's performance on the night.
"We didn't know how to handle it. It was really hard for Hendo after his early yellow card," he said. "We don't have to criticise the referee because he didn't decide the game but for the whole tournament it is difficult.
"There are a few yellow cards on each side and you think 'Why?' The team that goes through will have a problem with yellow cards."