Gigi Wijnaldum has warned his Liverpool teammates not to underestimate Manchester United on Sunday.

The fierce rivals are light years apart this season, with United 16 points behind the league leaders.

But Wijnaldum knows that Jose Mourinho's side can still cause them problems when they meet at Anfield on Sunday.

"It's a nice game and we'll try to put in the same performance that we did against Napoli," said Wijnaldum after Tuesday's 1-0 win over Napoli.

"Things can happen, everyone can have a bad season. I think the year before I came Liverpool finished eighth so those things can happen. That does not mean United are not a good team with good players.

"Last season with the same players they finished second. One season goes well, one season a little bit more difficult.

"It doesn't mean they have a bad team: they have good players, a good manager, and they know how to manage games and win games – or not to lose games. It is going to be difficult."