Ronald de Boer looks back on Rangers ' titantic tussles with Celtic and ranks as El Clasico as little more than a "family day trip" in comparison.
The Dutchman sampled two of the world's most famous derbies during a storied career but only one left him feeling like he'd undergone a religious experience.
De Boer signed for Rangers in 2000, famously turning down Manchester United despite a personal plea from Sir Alex Ferguson.
He scored one and set up another during his first experience of the derby cauldron as Dick Advocaat's side smashed their rivals 5-1 at Ibrox.
It's a day the 49-year-old will never forget as he explained why Barcelona and Real Madrid simply couldn't compare.
The former Barca midfielder told FourFourTwo: "Old Firm games were the most intense games I played in - you can't compared it to El Clasico in that sense.
"In Spain, people see it more as a family day trip.
"It's intense, but Rangers against Celtic is more extreme - you feel that the whole stadium is fanatically involved."
On the day he bagged and an assist in his derby bow, de Boer was struck by the almost cartoon-esque chaos unfolding all around him at Ibrox.
He added: "It was an incredible derby that I won't forget any time soon.
"I scored one and assisted another. The passion around that - religion, in a sense - is something else. It was unbelievable to experience.
"The games were always very physical. I remember some tackles where I was thinking, 'This can't be possible - back in Holland we would have had three or four red cards already!' The referees would just wave incidents away, or just give a free-kick at most.
"It was extreme, and sometimes it had nothing to do with football. It was a bit like what you see in cartoons, with a cloud of dust around the players fighting for the ball, which then slowly disappears as the ball is kicked away.
"That's the feeling I got."
