Pep Guardiola said Manchester City's FA Cup scare against Leyton Orient was an example of the magic that makes the competition "unbelievable". 

City had to come from a goal down to seal their progression to the fifth round after Jamie Donley's stunning effort bounced off the underside of the bar and in off Stefan Ortega. 

Substitutes Abdukodir Khusanov and Kevin De Bruyne struck after the break to confirm an important win for Guardiola's side, who take on Real Madrid in the Champions League knockout-stage play-offs next.

Despite being pushed all the way, the Citizens have now won their last 18 FA Cup matches against sides from a lower division, scoring 69 goals and conceding nine.

"We played a really good game, it was a typical FA Cup game - that's why this competition is unbelievable," Guardiola told BBC Sport.

"We knew that they were strong, and they'd run in the channels. They are a superb team and incredibly well managed, but we created a lot of chances. I'm happy to go through."

The defining moment in the contest came in the 79th minute when De Bruyne gathered Jack Grealish's pass in behind before poking the ball beyond Josh Keeley. 

De Bruyne has now been involved in 25 goals in his last 24 appearances in the FA Cup, scoring eight and assisting 17.

Guardiola was asked whether he was annoyed at having to rely on his quality in reserve to battle past the League One side. 

"Absolutely not, that is why they are here. We take this competition incredibly seriously, and we thought it was the best decision to make," Guardiola added. 

"I am happy about Kevin's goal, his movement was really good."

Phil Foden, John Stones and Bernardo Silva were some of the players introduced against Orient, despite a clash with Carlo Ancelotti's Blancos looming on Tuesday. 

The Citizens have endured an indifferent campaign so far, needing to win their final game against Club Brugge to reach the knockout stages of the Champions League. 

Guardiola's side also find themselves fifth in the Premier League, two points adrift of the top four and a further 15 behind leaders Liverpool, who also have a game in hand. 

But Rico Lewis, whose shot deflected off Khusanov for the equaliser, believes that with Guardiola at the helm, City can still have a special season.

"He [Pep Guardiola] wasn't going mad or anything like that. He knew we'd created chances, and it's about keeping going in an environment like this," Lewis told BBC Sport.

"Credit to Leyton Orient, they made it difficult for us to play. It's easy to say it's tougher than you think, but we all know they're tough. The crowd are right up for it.

"It's Man City at the end of the day, the demands are so high. There's enough leadership in this team. Going from attack to defence is difficult, there's a lot of ground to cover. 

"The season hasn't panned out how we wanted it to. Every game now, as long as we win, it could be a great season for us.

"Everyone wants us to get beat, apart from City fans, of course. It's pressure on our shoulders. Everyone settled their heads at half-time."