Rossi, a regular on the end-of-season spectacular at the Italian Grand Prix venue near Milan, last triumphed at Monza in 2007 and had to settle for second place behind Sebastien Loeb 12 months ago.
In Loeb’s absence this year, it was left to Rinaldo Capello to uphold Citroen honour in a DS3 WRC. However, the Italian veteran was unable to defeat Rossi, who was fastest on five of the nine stages to win overall by 2.8s in a Ford Fiesta RS WRC.
Capello, who was fastest on four stages, was second with Piero Longhi in third in a Citroen C4 WRC.
Rossi has tackled three rounds of the FIA World Rally Championship in the past. He has expressed a desire to take part on more rallies when he retires from bike racing.