Roma won away to Chievo but all Inter needed to do was match their result for a fifth consecutive Serie A title and eighteenth overall.
It was plain sailing from start to finish in Siena but Inter survived a scare in the sixth minute when Ekdal fired wide with just Julio Cesar to beat after receiving from Codrea and turning Maicon in the box.
Inter soon stepped into their stride and produced two clear chances inside a minute with Balotelli sending inches wide his first-time shot from Maicon’s cross, before Milito narrowly missed the target after being put through by Balotelli.
Siena goalkeeper Curci saved close-range headers from Milito and Thiago Motta, and got down at his near post to block Eto’o’s effort from the tightest of angles as Inter kept up the pressure.
The hosts raised their game when news filtered through that Roma had taken the lead against Roma and Maccarone severely tested Julio Cesar with a ferocious left-footed drive from 25 yards.
Balotelli was unlucky not to give Inter the lead seven minutes before the break when he saw his stunning shot on the turn from Maicon’s cross come back off the crossbar. Siena once again caused Inter’s fans hearts to skip a beat with their third clear scoring chance, but luckily for Inter, Samuel was able to block Jajolo’s low shot.
The second half was a continuation of the first. Inter continued to outplay their opponents and a great run by Zanetti created a chance for Milito, whose brilliant 20-yard strike is tipped over by Curci.
It was only a matter of time before the goal, and it came in the 57th minute when Zanetti powered his way past two Siena players and passed low to Milito who used the outside of his right foot to prod beyond Curci for his 22nd goal of the Serie A season.
Inter produced several clear chances to increase their lead. Substitute Stankovic shaved the bar with a trademark long-range effort, and Milito was denied by Curci with the flag going up for offside after Pandev’s rebound went in off the Siena keeper.
First the Coppa Italia, and now the Scudetto. Vamos a Madrid!