Aru had three top-five Grand Tour finishes to his name before arriving in Spain three weeks ago, most recently losing out to Alberto Contador on home soil at the Giro d'Italia earlier this year.
His decision to miss out on the Tour de France in July bore fruit in a crazy race dominated by crashes and controversy as none of the pre-race favourites made it onto the podium.
The four fastest men at the Tour decided to race again in Spain as Chris Froome reignited his rivalry with Nairo Quintana in a bid to become just the third man to win both races in the same year.
Alejandro Valverde and Vincenzo Nibali were also looking to add to their Vuelta wins in 2009 and 2010 respectively.
Yet, after the first stage team time trail was neutralized due to safety fears, Nibali was thrown out on the first day of real racing for being towed by his Astana team car.
Safety concerns were to be a consistent feature after a huge crash on the eighth stage left Belgian rider Kris Boeckmans in an induced coma for over a week.
Dan Martin and Tejay van Garderen were also left to count the cost of injuries from the same crash that forced them out of the race.
However, it was Oleg Tinkov, the outspoken owner of Tinkoff-Saxo who pushed hardest for action to be taken after two of his riders, Peter Sagan and Sergio Paulinho, were forced to withdraw after being mowed down by motorbikes.
Tinkov even threatened to pull the entire team from the race unless extra measures were put in place before the queen stage of the race in Andorra.
The stage designed by local favourite Joaquim Rodriguez was to add Froome to the growing list of casualties from the race as the Briton withdrew after finishing with a broken bone in his foot.
Movistar duo Quintana and Valverde also struggled to make an impact due to fatigue after standing on the podium behind Froome in Paris.
As in the Tour, Quintana improved in the final week to climb up to fourth overall with Valverde seven minutes off Aru down in seventh.
With the favourites struggling, Dutch rider Tom Dumoulin was the revelation of the race as he held the leader's red jersey for six days by showing impressive resistence in the mountains to go with his famed time trialing ability.
In the end, though, the Giant-Alpecin man admitted the race was just one day too long for him as Aru, flanked by Astana teammates, finally launched an attack on the penultimate stage that he couldn't live with.
Rodriguez had to settle for his third podium finish in the Vuelta in second, whilst Poland's Rafal Majka made the most of his chance to lead Tinkoff-Saxo in Contador's absence in third.
"It still hasn't sunk in," said a delighted Aru.
Once the dust settles he will realise that at just 25 he is now amongst the pantheon of riders to win one of the sport's three biggest races.
By Kieran Canning