Injury has deprived Milan of Ibrahimovic's services for much of the season but when he has started the goals have flowed to help Pioli's team to the top of the league standings.

"He is a champion in everything he does. With his comeback we have other tactical possibilities and we are very happy to have him," Pioli told reporters.

"He still manages to surprise me, even though I know him well by now.

"We must expect the best from him, but today he also did something beyond that."

Returning to the starting line-up for the first time in a Serie A match since a thigh injury suffered against Napoli on November 22, it took Ibrahimovic less than seven minutes to give Milan the lead as he scored from the penalty spot.

The strike ensured Ibrahimovic has scored in each of his past nine starts for Milan.

The Swede showed no weariness in his legs as he latched onto a long ball over the top to double Milan's lead in the 52nd minute.

In just eight Serie A games this season Ibrahimovic has scored 12 goals, second only to Cristiano Ronaldo's haul of 15 for Juventus.

Although Milan lost their unbeaten Serie A record while their top scorer was sidelined, they won five of their eight league games during the Swede's absence.

Milan top the standings with 43 points from 18 matches, three clear of city rivals Inter Milan and 10 clear of champions Juventus, who are fifth but have a game in hand.

Approaching the halfway point in the season, Milan will be hoping Ibrahimovic continues to keep up the scoring rate - he averages 1.73 goals per league game - as they chase a first Scudetto in a decade.

The only setback for Milan at Cagliari was the send off of substitute Alexis Saelemaekers, who received two yellow cards in quick succession shortly after coming off the bench.

Cagliari have lost five in a row and sit just one spot and one point above the drop zone after the winless run in Serie A was extended to 11 games.

Australian Associated Press