Victory saw Inter Milan return to the top of Serie A for the first time since winning the title last May, but only after the referee threatened to halt the game following racist chanting against Samuel Eto'o.
The abuse did not have any effect on the Cameroon striker, though, and he scored the only goal of the game in the 39th minute to take the Nerazzurri level with AC Milan at the top of the table.
Alessandro Matri was guilty of missing some good chances for an unluck Cagliari side, while Inter goalkeeper Julio Cesar will take a lot of the credit for Inter's win
The game had only just got under way when referee Paolo Tagliavento halted play. He had heard racist chants from the crowd aimed at Eto'o and requested an announcement was made over the public address system threatening the suspension of the game.
The calls had clearly not got to the Cameroon international, or perhaps they had inspired him to score the decisive goal with a touch of class. He controlled the ball and turned inside onto his left foot before shooting past Michael Agazzi from 20 yards.
The rest of the game belonged to the home side, however, with Julio Cesar making his first telling interventions early in the second half when he first denied Nene and then got up to push Matri's follow-up behind.
Eto'o had a shot tipped over the crossbar by Agazzi in the 52nd minute, but the Cagliari goal rarely came under threat.
The crossbar came to Inter's rescue in the 76th minute after a cross deflected off Cristian Chivu's head onto the woodwork and Daniele Conti pounced on the rebound, but he could not direct the shot past Cesar, who also reacted quickly.
Matri then lifted the ball over the crossbar from 10 yards in the 84th minute.
It looked like Cagliari could have played all day without scoring and they had to admit defeat as tiredness, both mental and physical, finally took its toll and Inter held on.
