De Jong's loan from Sevilla was expected to be terminated this month ahead of the forward joining fellow LaLiga side Cadiz for the remainder of the season.
However, the Netherlands international was required against Mallorca on Barca's return to action on Monday (AEDT) because of a spate of COVID-19 cases in the Blaugrana camp.
After twice hitting the woodwork, De Jong headed in his second league goal of the campaign in the 44th minute to seal a 1-0 victory for Barca in Palma.
In doing so, he became the first Barca player other than Lionel Messi to hit the frame of the goal twice in a single LaLiga game since August 2019.
With Xavi still waiting on other players to return to fitness, the recently appointed coach hinted De Jong may yet remain at Camp Nou for the rest of 2021-2022.
"He is an example of a professional," Xavi said after the win. "It is said that he can go out, but he works, he sacrifices himself. He is a hell of a professional.
"I am happy with him. Of course I am contemplating him staying because today he has been useful to us. He is an example for everyone.
"Depending on how you train, you will play. We will see the future. We will see if there are exits and entrances. But they are all hypotheses."
De Jong has scored eight headed goals in all competitions since the 2019-2020 season, a record surpassed only by Karim Benzema (13), Ante Budimir (11) and Youssef En-Nesyri (nine) among LaLiga players in all competitions.
It was also Barca's seventh headed goal in LaLiga this season, which is the most of any side and the same number it managed across 38 league matches last time out.
That match-winning moment helped Barca to just a second victory in six games across all competitions as it moved to fifth in LaLiga and within a point of fourth-placed Atletico Madrid, which also won in Monday (AEDT), beating visitor Rayo Vallecano 2-0.
Xavi was pleased with the fighting spirit shown by his side, though the win would not have been possible if not for an impressive save from Marc-Andre ter Stegen to deny Juame Costa in stoppage time.
🔥😲 This ASTONISHING late save from @mterstegen1 ensured a severely depleted @FCBarcelona took all three points away from @RCD_Mallorca and was celebrated as hard, if not more than @LuukdeJong9's earlier goal 😅 More here 👉🏻 https://t.co/8Z2T6Jux3W | #LaLiga #MallorcaBarca pic.twitter.com/gtx6EljjZ7— beIN SPORTS (@beINSPORTS_AUS) January 2, 2022
"There are three golden points," he said. "They way we played, and the circumstances we played in, this is a family victory. We have showed we know how to suffer.
"We had a very good first half and showed lots of personality. We are on the way up.
"We wanted the game to be suspended but I'm proud of the team, and proud of Marc. We needed him. He stopped a goal at the end and saved us.
"But the youngsters in the side are also helping us a lot. They have the right mentality and are well prepared. These three points put us in the fight for the top positions."
Riqui Puig was one of the many youngsters on display for Barca, the academy product making his landmark 50th appearance for the club in all competitions.
He completed 66 of his 69 passes for a passing accuracy of 96 per cent that no other Barcelona player could match on the day.
"Riqui was very good," Xavi said. "As were the others, like [Oscar] Mingueza and [Ferran] Jutgla. They have all worked hard for the team and it is exciting for us.
"This is the way forward and this victory is an example of that."
Dani Alves and Jordi Alba missed the win after testing positive for COVID-19, but the pair has since returned negative tests and has been given the green light to return to training from Tuesday (AEDT).