Steve McManaman does not lack perspective when he says there is nothing in football as seismic as a meeting between Barcelona and Real Madrid. As a Liverpool player he faced Manchester United on countless occasions, in matches that decided the destination of the Premier League title. He played in Merseyside and Manchester derbies too. Yet none were as exhilarating, awe-inspiring or downright frightening as playing in a Clásico. Not even the passion of an FA Cup final between Liverpool and United could match it.

The Clásico could be four weeks away and it would still be all anyone in Spain was talking about. If McManaman, who played for Real between 1999 and 2003, stopped to put petrol in his car, the conversation would inevitably turn to Barcelona. Beating Barcelona. Above all, not losing to Barcelona. The buildup was almost as intense as the match itself. Losing was not an option.

"It was immense," McManaman says. "It was bigger than any other game I'd played in, bigger than Liverpool v Manchester United games and Liverpool v Everton. It's not necessarily a derby, it's just a weird rivalry. I knew that Barcelona were our rivals but it seemed to mean more to the Spanish players because of the history. We don't have different types of languages or newspapers in England. We don't have rivalries between communities and governments and even your own newspapers."

As an Englishman abroad, it was stressed to McManaman, who won the European Cup twice with Real, even scoring in the final against Valencia in 2000, how important the fixture was. For the Spanish players, nothing mattered more than beating Barcelona. When they did, which happened more often than not during McManaman's time, it was bedlam.

"There's a lot of hatred there because it's the Catalans against the Spanish regions and they [the Catalans] want autonomy and independence," McManaman says. "As an Englishman over there, you were set apart from that because you didn't necessarily understand the full history of the Spanish and the Catalans but for the players who were born in Madrid, it meant a lot going there and getting the right result.

"Whenever you got the right result, they were over-exuberant in the dressing room. They were so, so pleased. Over the league campaigns, we were quite dominant over Barcelona. We always finished higher than them and they were not necessarily a threat to us in the league.

"We knocked them out of the Champions League semi-final in 2002. We beat them 2-0 at their place in the first leg and the celebrations in our dressing room were incredible. It was mainly led by the Madrid-born players because they knew how big the victory was, so you fully understood it all then."

McManaman scored a delightful chip in that match – "a great feeling" – but he admits it was difficult to grasp precisely how much the fixture meant, and harder still to deal with the asphyxiating pressure and nonsense that attaches itself to it. A trip to Camp Nou was sometimes like journeying into a war zone. It was not for the faint-hearted.

"In Barcelona, it was extremely hostile," he says. "It was quite scary going from the hotel to the stadium, and during the game itself the crowd was very volatile. From the hotel you had people ringing you up all night, people beeping the horns outside. From the hotel to the stadium we had police running either side of the coach with guns.

"Bricks were being thrown at the bus all the way along. Anything to try to put you off. In England that's just absolutely unheard of and hopefully it's unheard of now in Spain. Back then it was a scary, exciting time to go there but it was very different from what I was used to."

At least it gave them an edge when they got into the stadium. "When the stones are bouncing off the windows and you're crouched in the middle of the bus with curtains closed and then you finally get under the stadium, you are on edge. You want to get out there and play. More importantly you want to get out and beat them."

This was the era of the Galacticos, Real's squad packed with some of the best players in the world. There cannot be many experiences more surreal than crouching down on the bus next to Ronaldo and Zinedine Zidane while your bus is getting assaulted. "To be crouched alongside numerous world player of the years while the windows of your bus are nearly getting smashed in is a strange old feeling," McManaman admits.

Probably not quite as strange as a pig's head being lobbed on to the pitch during a game though, which is what happened when Luis Figo returned to Camp Nou in 2002 after doing the unthinkable and joining Real from Barcelona in 2000. "Everything was thrown on, empty whisky bottles, golf balls, mobile phones," says McManaman, now a pundit for ESPN. "The referee suspended the game at one stage."

Although Figo had emulated Bernd Schuster and Michael Laudrup by leaving Barcelona for Real, he did not expect such a fierce reaction. "You knew the divide was difficult and that you had to be very mentally strong," McManaman says. "But I don't think he ever thought it would be that volatile. I don't think anybody had seen anything like that.

"It was a shock that he had come from Barcelona because he was such an outstanding player. When he played for Barcelona he used to have so many run-ins with the likes of Roberto Carlos. I remember Roberto getting sent off for a terrible challenge on him so you always think it's impossible for players to come to certain teams yet at certain times it does happen.

"It probably surprised me that Luis came because he was world player of the year and he left for the biggest transfer fee ever at the time. But it enhanced Real Madrid."

This Clásico is a role reversal of last season's matches. Then, Barcelona were the ones chasing. This time it is Real who are lagging and they trail Tito Vilanova's side by eight points after six games. Barcelona have won their first six. Real have lost twice already; a third defeat would be potentially fatal to their chances of retaining the league title.

"If Barcelona win, 11 points is a lot," McManaman says. "Unfortunately when your biggest rivals are as strong as they are, to be eight points behind after six games is very difficult. You'd only expect Barcelona to lose or draw a couple. When you see Barcelona with a full-strength squad they look like they're never going to lose a game.

"The pressure would certainly be on José Mourinho. But if they win, everyone will be nice and calm – then it's only five points. I know which side you'd rather be playing on though."

ESPN has televised coverage of two other top matches on Sunday: Milan v Internazionale at 7.15pm and Marseille v PSG at 10.30pm. Visit espn.co.uk/tv for details.