Pep Guardiola has warned his Manchester City side they must put their brittle Champions League tendencies behind them as they prepare to welcome Real Madrid to the Etihad Stadium.

Guardiola has swept the board in terms of domestic honors since joining City in 2016, with this season's EFL Cup the sixth major honor of his tenure.

He has been unable to end his club's wait for a maiden Champions League title, however, with Tottenham and Liverpool ending their compatriots' involvement at the quarter-final stage in the past two seasons.

City hold a 2-1 advantage over Madrid heading into the second leg of their last-16 tie on Friday, with a place at the concluding mini-tournament in Lisbon up for grabs.

But their 3-0 defeat at Anfield in 2018, where all of Liverpool's goals came within the space of 19 first-half minutes, serves as a cautionary tale, as do the clusters of goals conceded against Monaco – in 2017 – and Tottenham when departing on away goals on those occasions.

"Yeah definitely," Guardiola told a news conference when asked whether it was a concern. "More than conceding a goal is the way we concede a goal.

"When they are brilliant and make a good action, we have to accept it.

"But most of them were goals we could have avoided. We have to avoid it. Making mistakes in this competition punishes you a lot.

"We know it. We spoke about it many times, not this week but the last years, many times. If we want to make a step forward as a team to be close to winning this competition, we have to be better in this area."

If City progress, Guardiola will become the first coach to defeat Zinedine Zidane in a European knockout tie after the Madrid boss masterminded a run of three Champions League triumphs in a row from 2015-16 to 2017-18.

"When you think that you've got one of his tactical plans covered, he'll hit you with another tactical plan or revert to the original one that you thought he was going to start with," he observed.

"In the dim and distant past, we played the first leg and what we can remember from the first leg we've put to good use.

"We spoke about that game and since then we've watched all Madrid's games since LaLiga restarted.

"We've spoken about how we think Madrid might approach this game. But what we've done more in these past two weeks is talked about what we can do – how we can hurt Madrid and areas we can cause problems for them."

Guardiola's preparations for the game have been thrown partially into flux by the news that teenage centre-back Eric Garcia has declined a new contract at City.

Garcia established himself as the first-choice partner for Aymeric Laporte over recent weeks but has been heavily linked with a return to his boyhood club Barcelona.

At the other end of the field, Sergio Aguero remains sidelined having undergone meniscus surgery, but Guardiola is not ruling out having City's all-time record scorer back for the final stages, should they negotiate Madrid.

"Right now, I don't know," he added. "He is still in Barcelona [where Aguero had the operation]. He is getting better. I spoke with the doctors and everything is like we thought.

"Hopefully he can come back and start training with us, but I don't know."