Liverpool cruised into the fifth round of the FA Cup with a 5-2 rout of Championship Norwich City on Sunday, to kick off Juergen Klopp's long goodbye at Anfield, while crowd trouble marred Wolverhampton Wanderers' 2-0 victory over West Bromwich Albion.

Twelve-time winners Manchester United gave up a two-goal lead before escaping Rodney Parade with a 4-2 victory over fourth-tier Welsh side Newport County.

Liverpool's beloved manager announced on Friday that he would leave the Merseyside team at the end of this season, his ninth at the helm.

"I get it, it's very emotional," Klopp told the BBC. "I just have to make sure that I don't get on that side of it. (And) in the games, we need to be warriors and not celebrate the old man on the side lines.

"First match after the news and we can get used to it," he added.

The eight-time FA Cup winners had goals from Curtis Jones, Darwin Nunez, Diogo Jota, Virgil van Dijk and Ryan Gravenberch.

Liverpool will next play either Watford or Southampton after that fourth-round game earlier on Sunday ended in a 1-1 draw thanks to a last-gasp goal by Southampton's Stuart Armstrong to force a replay.

"It was a perfect game," Jones told ITV. "There were loads of goals scored and we didn't have any injuries.

"Definitely (can use Klopp's departure as motivation)," he added. "We had our goals at the start of the season and now the news is out, we'll be giving it more."

Ben Gibson and Borja Sainz scored for Norwich City, who are ninth in the Championship, 28 spots below Premier League leaders Liverpool in England's football pyramid.

Antony scored in the 68th-minute for last year's FA Cup runners-up Manchester United after Newport -- ranked 76 places below United in England's football pyramid -- had clawed their way back from two goals down.

"We controlled the game, maybe we went a little bit slower," United manager Erik ten Hag told the BBC. "We had the chance to go 3-0. (Alejandro) Garnacho hit the crossbar. (Newport) had nothing, really nothing and then they scored a goal."

Bruno Fernandes, 18-year-old Kobbie Mainoo and Rasmus Hojlund also scored for United, who conceded two goals in an FA Cup match against a fourth-tier side for the first time since 1970 (against Northampton Town).

"Obviously it was not the result that we wanted, we got the win that we wanted but the result was not the perfect one for us. We didn't want to concede goals," United captain Fernandes said.

"We know that to make the season look not as bad as it has been, we have to try to win this trophy ... we know how much the FA Cup means for our fans, our club, for the country and it's important for us too. We want to get into the final and win."

Wolves' victory in their fourth-round match at West Brom was interrupted for nearly 40 minutes due to clashes involving the two sides' supporters.

Wolves were leading 2-0 when projectiles were hurled on to one end of the pitch in the 82nd minute, sparking a brawl in a corner at The Hawthorns.

Matheus Cunha and Pedro Neto scored for Wolves, whose manager Gary O'Neil called the disturbances "really disappointing".

"Up until that point it was a good tie with good atmosphere," O'Neil told ITV. "How people behave at football is really important and we need to look at that, make sure everyone is safe. When we came back out the atmosphere had gone, it was really sad to see."

The Football Association has launched an investigation into the disturbance that led to two arrests, calling it "completely unacceptable."

The delay prompted officials to push back the draw for the FA Cup fifth round -- originally scheduled for just before the Liverpool-Norwich 1430 GMT kickoff -- to halftime of that game.