His countryman Youssef Baba provided the service, sacrificing his own ambition in the final, he took the pace out in 54.14, the two Moroccan teammates leading the two Kenyan challengers Noah Ngeny and Bernard Lagat, separating from the rest of the field.
Baba disappeared quickly leaving El Guerrouj to burn off the Kenyans taking the third lap in 56.90.
Through the final turn Ngeny executed a textbook kick, moving onto El Guerrouj's shoulder, sliding into the second lane and sprinting past him for the gold.
Lagat moved into lane 3 with hopes of passing as well but ran out of real estate to take the bronze.
El Guerrouj had been disappointed by the finish in Atlanta; expected to challenge for gold, he had tripped and fallen.
Each National Olympic Committee was permitted to enter up to three athletes that had run 3:36.80 or faster during the qualification period.