Inter Milan retained their Serie A title on Sunday and then announced they had agreed a four-year contract extension with coach Roberto Mancini.
Their 2-1 win over Siena, along with a 2-1 loss for second-placed AS Roma at Atalanta, gives Inter an unassailable 16-point lead with five games to go.
Defender Marco Materazzi scored both goals to clinch the victory and a 15th championship for Inter.
"The emotion is immense. We have had an extraordinary campaign," said Mancini.
"It is extraordinary to win five games from the end with a lead of 16 points.
"The team showed great character. I'm happy for all Inter fans," added 42-year-old.
Mancini, who has agreed to a deal to stay until 2011 with an option for a further year, had been linked with the Chelsea job earlier this season.
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Inter went into the game on the back of just two points from their last three matches and suffered their first league defeat of the season against Roma on Wednesday.
By winning the title with five games to spare, they match the record set by Torino in the 1947/48 season and equalled by Fiorentina in 1955/56.
Last year Inter were awarded the scudetto in July after Juventus were stripped of the title following the country's match-fixing scandal.