Scarlets' replacement fly-half Gareth Bowen kicked a superb 50-metre penalty goal in the dying minutes to steal a victory that Wilkinson looked to have handed the Falcons on a plate with a fine performance off the bench. Scarlets director of rugby Gareth Jenkins praised his pack after the gritty win.
"We felt we had the edge up front, and it's something we've been working very hard on," he said. "Gareth is a great kicker of the rugby ball. The kick was a long way out but I was sure he'd get it.
"It's great to win - especially for the Stradey Park crowd who gave the game so much atmosphere."
Wilkinson was on the pitch after only 17 minutes to replace the limping Toby Flood, and everything he touched turned to gold as the Falcons turned a 7-3 deficit into a 13-7 lead in the space of 10 minutes.
Wilkinson's darting run forced the Scarlets to concede a penalty - which he converted - before a crunching tackle on Dafydd James ended a promising move from the home side. The World Cup hero then produced a pinpoint cross-kick for winger Anthony Elliott to score the Falcons' first try, and added a sideline conversion for good measure.
The Scarlets scored tries on either side of the break through hooker Aled Gravelle and fly-half Mike Hercus to retake the lead, but the biggest cheer of the afternoon came when Wilkinson missed a shot at goal. The fans weren't cheering a few minutes later when Wilkinson's skip pass put winger Tom May over near the posts, and a yellow card to lock Inoke Afeaki didn't help the home side's cause.
The Scarlets shrugged off the one-man deficit, though, and Bowen's beautifully struck penalty goal gave them a two-point lead they held on to during a frenetic final five minutes. Wilkinson had a chance for glory in the last seconds, but went for the gap instead of the dropped goal and the move broke down. The best news for England fans, however, was that Jonny Wilkinson didn't break down.
Tries - L Byrne, A Gravelle, M Hercus
Pen - G Bowen
Cons - M Hercus 2
Tries - A Elliott, T May
Pens - M Burke, J Wilkinson
Cons - J Wilkinson 2
Halftime: Newcastle 13-12.
Yellow card: Inoke Afeaki (Scarlets)
Referee: Nigel Williams (Wales)