The 25 year-old Sardinian wears number one in the Italian race around the hills of Varese, north of Milan, with fellow Italian Grand Tour contender Vincenzo Nibali also in the Astana line-up. Major rivals include Thibaut Pinot (FDJ), Frank Schleck and Giacomo Nizzolo (Trek Factory Racing) and Vuelta stage winner Kristian Sbaragli (MTN-Qhubeka).
Aru was not part of the Italian national team in Richmond and will not be part of the Astana team for Sunday's Il Lombardia due to sponsor obligations forcing him to ride the Tour of Almaty in Kazakhstan. He will ride Thursday's Milan-Turin and then end his season with the Abu Dhabi Tour.
Since winning the Vuelta a Espana, Aru has kept training, even going out for a ride with Lugano neighbour Alberto Contador, who beat him to win the Giro d'Italia in May.
"In the last few days I've had a chance to take in what it feels like to win the Vuelta, I've watched the videos of the race and enjoyed my victory. I haven't celebrating that much. I've done some extra things in the afternoons and some interviews but I’ve always kept my morning clear for training," Aru explained to Gazzetta dello Sport.
Aru is not expecting to win the Tre Valli Varesine race after the huge effort he made to defeat Tom Dumoulin (Giant-Alpecin) at the Vuelta.
"I haven't had a lot of time to recover and so it will depend on how I feel. I finished seventh in 2013 but that was on a different course," he explained.
"I'm riding Milan-Turin on Thursday too and then I head to Kazakhstan for the Tour of Almaty on October 4. From there I'll travel to Abu Dhabi."
Aru admitted he would have liked to ride Sunday's Il Lombardia but sponsors obligations come first.
"I saw the new finale with the climbs of the Ghisallo, Sormano, Civiglio and San Fermo della Battaglia the other day and it's a great finale. But you've also got to understand the sponsors. I ride for a Kazakhstani team and it's only right they get to see me too."