David Suazo gave the hosts the lead with a superb finish after only 11 minutes, before Julio Cruz's close range effort made it two on the half-hour mark.

However, Atalanta ensured Inter did not have it all their own way when Sergio Floccari lashed in a brilliant reply for the visitors six minutes before the interval.

Both sides had chances to add to the scoreline after the restart but Inter did enough to secure a crucial victory after substitute Simone Inzaghi was dismissed for his second yellow card in injury time.

The result means Inter lead second-placed Roma by three points after the Giallorossi's 1-0 win at Genoa.

Inter boss Roberto Mancini opted to start with Suazo and Cruz in attack, leaving Zlatan Ibrahimovic on the bench.

Cristian Chivu was deemed fit enough to start after missing Romania'sEuro 2008 qualifier against Albania on Wednesday with a leg injury.

And Marco Materazzi found himself on the bench having been sidelined for the past two months with a thigh problem.

Luigi Del Neri, meanwhile, dropped Riccardo Zampagna from Atalanta's squad after the pair had a bust-up earlier in the week.

The encounter got off to a laboured start with neither side taking control in the opening exchanges.

But it was the hosts who broke the deadlock with the first meaningful attack of the match.

Suazo broke clear into the Atalanta penalty area and played a neat one-two with Cruz before firing a deft shot which drifted past Ferdinando Coppola and clipped the post before nestling into the bottom corner.

Cruz had a good chance to double Inter's lead midway through the first half but he could only fire his effort wide after beating two defenders.

Yet the Argentina international did not have to wait long before registering his name on the scoresheet as he reacted quickest to stab home after Suazo's cross had rebounded off a post.

The home side looked to be cruising to the half-time interval until Floccari gave Atalanta fresh hope just before the break with a powerful drive from the edge of the area after a superb solo run.

The visitors started the second half exactly where they left off at the end of the first and were unlucky not to draw level when Adriano Ferreira Pinto's shot across goal eluded everyone.

Cruz then headed a great chance over the crossbar for Inter as both sides looked capable of finding the net.

Inzaghi replaced goalscorer Floccari after 79 minutes and the striker received his first booking seven minutes later, before being shown a second and a subsequent red in injury time.

The win preserves Inter's unbeaten record so far this season and sends Atalanta down to seventh place.