MONZA, Italy, Sept 4 (Reuters) - Germany's Nico Rosberg won the Italian Grand Prix for dominant Mercedes on Sunday to cut team mate Lewis Hamilton's Formula One world championship lead to two points with seven races remaining.

Triple world champion Hamilton, who had been on pole position as favourite to take his 50th career victory and third in a row at Monza, finished second after a slow start gifted Rosberg the race.

Rosberg's first victory at the historic circuit outside Milan was his seventh of the season, one more than Hamilton, and 21st of his career.

Ferrari's Sebastian Vettel and Kimi Raikkonen finished third and fourth at the team's home race with Australian Daniel Ricciardo fifth for Red Bull.

(Reporting by Alan Baldwin, editing by Toby Davis) ((alan.baldwin@thomsonreuters.com; +442075427933; Reuters Messaging: Reuters Messaging: alan.baldwin.reuters.com@thomsonreuters.net))