Raul equals Muller scoring record
Raul matched the German forward's 32-year-old tally when he pounced on a fumble by Milan goalkeeper Dida and slotted into the empty net in the 19th minute of the Group C clash at the Bernabeu on his 126th Champions League appearance.
"Raul's goal showed how sharp he is," Raul's Brazilian teammate Kaka told reporters. "He is always incredible and is a player who has broken all the records."
"He's the first one into work every time and never tires and that's why he continues to be a key part of the team."
The former Spain international, 32, had scooped the ball over Dida from close range in the second half after Kaka's shot but the effort was ruled out for offside.
He was also involved in a scuffle with Milan's former Barcelona playmaker Ronaldinho for which he was booked.
The three main European competitions are the European Cup/Champions League, Cup Winners Cup and the UEFA Cup/Fairs Cup.
Club captain Raul, who netted twice in Real's 4-2 La Liga win over Real Valladolid on Saturday, has scored all 66 goals in the Champions League.