The Spaniard played the first half for his current club before swapping shirts at half time to give over 60,000 fans inside the Arena AufSchalke one final glimpse of him in a Schalke shirt, and he scored twice in a 9-0 victory for the Bundesliga side.
His first goal, Schalke's eighth, was set up by a delightful backheel from Julian Draxler, who paid tribute to the 36-year-old, who left Gelsenkirchen after two seasons a year ago.
"I owed that to him," said Draxler to Sport1 television. "He has done so much for me.
"He could not have bid farewell without scoring a goal. The whole of Schalke can be proud of the fact a player of Raul's stature once played for us here."
Klaus-Jan Huntelaar was on target twice with new signing Leon Goretzka also scoring as Schalke stepped up preparations for the start of the Bundesliga season in a fortnight.
Elsewhere, Hamburg recovered from conceding an early goal to draw 1-1 with Inter Milan while Bayer Leverkusen demolished Dutch first division side Vitesse Arnhem 4-0. Last season's Bundesliga top goalscorer Stefan Kiessling grabbed a brace just a day after committing himself to a new four-year contract with Leverkusen.
There were also wins for Eintracht Frankfurt, Nurnberg and Borussia Monchengladbach over Luxembourg, Leeds and Celtic respectively.
Bundesliga newcomers Eintracht Braunschweig were crushed 3-0 by West Ham on their official season opening day while Augsburg were beaten 1-0 by last season's Champions League quarter-finalists Malaga.
Freiburg also faced Spanish opposition, and came away with a 0-0 draw against Athletic Bilbao, while Stuttgart beat Akhisar Belediyespor 2-0 with Antonio Rudiger and Timo Werner on target.