The 22-year-old opened the scoring just before half-time.
Jamaal Lascelles has explained that he decided not to celebrate his goal against Swansea as he wanted to wait until Newcastle had won the game before getting carried away, the Shields Gazette reports.
The defender opened the scoring five minutes before the break at St James' Park before Moussa Sissoko and Andros Townsend sealed a massive win for the Magpies in the final 10 minutes of the contest.
And while Lascelles' goal would have been a huge relief to those around Tyneside, the centre-back explained that it did not feel right to go over the top.
"I wasn't going to celebrate at 1-0 - not until the 90th minute, when we had the game won," he told the Shields Gazette.
"I was pleased to get the goal but more importantly for me as a defender was the clean sheet.
"Everyone worked hard around the pitch defending that position, and we've seen a lot of players talking which has helped massively. It's nice to see a reaction. We have to keep it like that now."
Despite not making his debut for the club until this season, the 22-year-old has quickly established himself as a key man in their survival fight.
His pleas for more heart and desire following the Southampton defeat (via Shields Gazette) saw him earn a lot of respect for his honesty and willingness to stand up to the more senior members of the squad, and his goal against the Swans could now prove to be a turning point in their season.
It was the only time in their last eight games that Rafa Benitez's men have taken the lead in a game, and in the previous fixtures in that run, they had claimed just one point.
And with the victory taking them to within three points of safety, Lascelles will be hoping that he can inspire the side to the points they need to get their heads above water.