Pep Guardiola hailed "two incredible goals" from exciting England prospect Phil Foden as Manchester City comfortably negotiated a testing FA Cup mission against Newport at Rodney Parade.

Foden struck twice in the second half to help steer City home 4-1 following a scoreless first period.

And City boss Guardiola was quick to shower praise on the 18-year-old.

"Phil's only problem is that he has to compete with Kevin De Bruyne, David Silva and Bernardo Silva," Guardiola said.

"He's a player who is ready to play. Today was a good test for him, and this will be good for him.

"He learnt a lot and he helped us to win the game with two incredible goals.

"He has the mentality and ability to score goals when he is near the box. He was brilliant."

City kept their quadruple hopes alive as Leroy Sane and Riyad Mahrez also struck in the second period to ensure City's class eventually told against opponents 82 places below them on the league ladder.

Padraig Amond maintained his record of scoring in every round for Newport two minutes from time, but hopes of a dramatic comeback were brief as Foden's second and Mahrez finished the job.

Newport have beaten Leeds, Leicester and Middlesbrough, as well as drawing with Tottenham, at Rodney Parade in the last 14 months, and they again emerged with credit for frustrating City for so long.

Guardiola added: "It was really tough. What they (Newport) do, they do incredibly well.

"Every free-kick and throw-in is difficult, and we suffered in the first 20 minutes because we needed time to adapt.

"We finished well and we produced an incredible performance in the second half.

"I'm so delighted to keep going in this incredible, prestigious competition, and now we are in the quarter-finals, so I must say well done to the players.

"Football is not always playing on the biggest stages and on good surfaces. We had to adapt, and it can only help us be a better team.

"We can play at home against Chelsea and do a good performance, but coming here is completely different with the different opponent, different approach and the atmosphere and everything.

"I am quite surprised with the atmosphere. The support of the team was incredible, it was nice to hear them chanting 'Who are you? Who are you?'"

"If you come here and don't take it seriously, big teams will go out, and they have. Sometimes it's easier to play against Arsenal and Chelsea and in the Champions League."

Newport's cup run is now over for another season, but they have made more than £1million from it and kept themselves firmly on the football map.

County boss Michael Flynn said: "I am very proud of the players. I thought they were outstanding.

"I am a little bit disappointed with the last two goals we conceded, because we got back into it and we just wanted that one chance, but we didn't hold on.

"I was buzzing at half time, especially after watching them (against Chelsea) last week. They were 4-0 up after 24 minutes against a much bigger club than us.

"Getting to share the touchline with Pep Guardiola was magical for me. He said 'you should be proud, you are doing a fabulous job, and good luck'.

"Manchester City are such an excellent team. The players are full of class, the manager is full of class. They invited our players into their changing room, and that means a lot for any player, especially League Two ones.

"I can't speak highly enough of Manchester City and their manager. He is a serial winner and he is also full of respect."