Pep Guardiola has claimed Jurgen Klopp's Liverpool have been the toughest rivals of his managerial career.

Guardiola's Manchester City side fell to a 5-1 aggregate defeat to Real Madrid in the Champions League last 16.

Madrid have now eliminated Man City in five knockout ties in the  Champions League, including in four of the last five seasons. Indeed, only Bayern Munich have been eliminated more times by one side in knockout ties in the competition’s history.

Guardiola, meanwhile, has lost four of his last five Champions League meetings with Madrid (W1), after only losing three of his first 12 matches against them in the competition (W5 D4).

The former Barcelona coach has always had a fierce rivalry with Los Blancos. He has faced them 30 times across his career, only going up against Arsenal (33), Chelsea (31) and Manchester United (31) on more occasions.

Guardiola's record against Madrid stands at 14 wins, seven draws and nine defeats (not including penalty shoot-out losses).

But the Man City boss insisted it is Klopp's Liverpool who posed the fiercest challenge.

"No, my biggest challenge was Jürgen Klopp with Liverpool, in these years here," Guardiola said in a response to a question from Spanish media.

"You were in Spain, you didn't realise what that competition was.

"It's been a good learning experience for the club, because this is a club that 12 or 13 years ago was never in Europe. Playing so many times against Real Madrid, with the generation we've had, we've done it.

"They've won, we've won. The numbers are similar, they've knocked us out more than we have them. But they know how we've played."

Guardiola has gone up against Klopp 30 times, more than any other manager.

He has won just 10 of those matches, losing 11 times to the German.

Of those 30 meetings, eight came during Guardiola's stint as Bayern coach, while Klopp was at Borussia Dortmund.

Under Klopp, Liverpool won the Premier League in 2019-20. In every other season between 2017-18 and 2023-24, the title was won by Guardiola's City.

The Reds finished within a point of City in 2018-19, and once again in 2021-22.

Guardiola faced Klopp's Liverpool 16 times in the Premier League, with City winning five of those games, losing four and drawing seven.

However, Guardiola's team did score 31 goals to Liverpool's 20 across those meetings.