The France midfielder marked his home debut with a 68th-minute strike to level the game at 2-2 and then blasted home a brilliant winner to further boost Pardew's survival mission.
Chelsea looked to be on their way to a first victory in four attempts in all competitions when, after Frank Lampard had cancelled out Jonas Gutierrez's first-half opener by scoring his 10th Barclays Premier League goal of the season for the 10th successive campaign, Juan Mata curled home a superb 61st-minute effort.
But a rejuvenated Newcastle refused to accept defeat and Sissoko snatched a dramatic win which was secured when Steven Taylor blocked Lampard's goal-bound effort deep into injury-time.
Asked if he had seen a better home debut, Pardew replied: "Not since I have been here.
"[Papiss] Cisse made an instant impact when he arrived, but our fans, who are an intelligent set of fans - these people love their football here.
"They told me last time [in the 2-1 home defeat by Reading] that they didn't like me, that my subs were all wrong - and they were probably right.
"But they know a good player when they see one. He didn't just give us the goals, he gave us a lot more than that.
"I remember seeing him at Toulouse about 14-16 months ago and there are only two players that I have seen that I was desperate to get here. One was [Yohan] Cabaye and one was Sissoko and we have managed to do that."