The notoriously shot-shy Netherlands midfielder continued a prolific run by his own standards with a second goal of the season to put Milan ahead against Fiorentina at the weekend.
But Josip Ilicic struck after half-time to ensure a share of the spoils and leave De Jong and his team-mates sixth in the Serie A table with after eight matches with 15 points to their name.
A lacklustre effort last season resulted in Milan missing out on their customary place in the Champions League and De Jong is keen to regain a seat at European football's top table at the earliest possible opportunity.
He told Milan’s official website: “Fiorentina only had one chance and they scored. We were a bit tired and we’re taking home just one point. This is football, but our objective remains to finish in the top three.
“We have another match on Wednesday and we want to pick up the three points. We have to win against Cagliari to remain on track and reach our objective. It won’t be easy, but we have to always believe."
De Jong returned from suspension to boost a Milan midfield still lacking long-term injury victim Riccardo Montolivo and the former Manchester City enforcer became the latest San Siro star to praise the fledgling reign of coach and former crowd favourite Filippo Inzaghi, who took over from Clarence Seedorf at the helm during the close season.
"The coach has done a good job with us, he’s always very positive," De Jong added.
"We believe and we never give up, just like our fans. We do this for our fans and for the club, which is very important."
Giacomo Bonaventura could push for a start after Inzaghi paid tribute his contribution from the bench against Fiorentina, and the midfielder would face a Cagliari outfit in high spirits after their crushing 4-0 win at Empoli on Sunday.
All of Cagliari's goals arrived in a frantic 16 minute period that closed the first half, with Marco Sau and Albin Ekdal on target either side of a Danilo Avelar brace.
Veteran coach Zdenek Zeman was full of praise for his team's display and is delighted with the depth of quality in his squad.
“I am happy because I have so many quality players at my disposal and they make it difficult every time to choose a starting XI," he told reporters.
"If a player has the slightest problem in training, I keep him to one side until he has recovered 100 per cent for the next games."