Pep Guardiola acknowledged Manchester City have to improve defensively if they are to overcome Real Madrid and reach the Champions League final for the second successive year.

City take a 4-3 lead into Wednesday's semi-final second leg at the Santiago Bernabeu following a thrilling contest in Manchester last week.

Premier League leaders City held a two-goal lead on three separate occasions but, inspired by Karim Benzema, Madrid ensured the tie remains firmly alive.

City will be boosted at the back for the return fixture, however, as Joao Cancelo returns from suspension and Kyle Walker is expected to be fit to feature.

The England international has not played since injuring his ankle against Atletico Madrid last month, but he was back in training on Tuesday and is part of City's squad.

And Guardiola, who confirmed John Stones is injured, accepts that City must be stronger at the back if they are to see out the job.

"Probably, we have to be better but we can play much worse than we played and we can win," he told a news conference.

"Sometimes you get what you don't deserve, sometimes you don't get what you deserve. We have to perform incredibly well and win the game.

"Last week's game is in the past. The tie is 180 minutes. We try to do better than what we have done. We go there for that and everyone is ready to try to do it."

Pushed on whether he expects Walker to be ready to start, Guardiola added: "He trained, he'll travel and we decide tomorrow. I'm happy he's back."

City had registered clean sheets in their previous four knockout matches, keeping Sporting CP and Atletico quiet in the last 16 and quarter-finals respectively.

The 26 shutouts City have kept across 53 games this season is the third-most of any side from Europe's top five leagues, behind Chelsea (27) and Liverpool (31).

Reflecting on last week's tie, the joint-highest scoring first leg in Champions League semi-final history, Guardiola said: "It was a lovely open game.

"The fact the teams scored seven goals between them. We were happy, we could have maybe got a better result but also a lot worse. 

"You look at it, recover the next day, analyse it in the cold light of day. For better or worse we always knew this would be over two games. 

"The Etihad and the Bernabeu. To knock Madrid out you have to perform well over two games."

Guardiola has won four Champions League matches against Madrid – only Ottmar Hitzfeld has won more (seven) – with two of those wins for the Catalan coming at the Bernabeu.

In the opposite dugout is Carlo Ancelotti, who last week celebrated becoming the first manager to win each of Europe's top five leagues.

Guardiola praised Ancelotti for his achievement but insisted Madrid's players will not have lost focus.

"Congratulations to him for winning the Spanish league," said Guardiola, who won three LaLiga titles with Barcelona. "I did it, he did it last week. 

"I admire him. He's been all over the world, big football countries and fantastic teams. It's always incredibly tough, the football is really good. 

"Part of that is he's an exceptional person. Every time with him he's calm, controls his emotions perfectly."

Should City complete the job, they will become the fourth English side to reach consecutive European Cup or Champions League finals.

But Guardiola conceded the experience of competing regularly in the latter stages of the competition does not guarantee lessons have been learned.

"Experience... the question is what to learn from the experience," he said. "You could make the same mistakes. It's completely different, it's difficult to compare to last season. 

"How will the guys wake up tomorrow? The fact we've been there quite often in the last years, we've been here and done well and know how to handle the situation. 

"But it's not a guarantee to play good. They know we have to perform well and our best to reach the final."