Goran Pandev, Walter Samuel and Diego Milito struck the goals in Inter's 3-0 victory.
“This was an important victory, especially as it takes us 10 points clear of second place,” said Mourinho.
“Cagliari are not an easy side to face and even when 2-0 down they never gave in, creating quite a few problems for us.
“We remained solid and compact to ensure we kept a clean sheet. I was particularly impressed with Goran Pandev, he's in great shape.”