And they all lived happily ever after.

Newcastle coach Michael Hagan says Andrew Johns has written the final chapter in a fairytale fortnight after the Knights captain landed a sideline conversion after the bell to sink St George Illawarra in a 32-30 National Rugby League thriller at EnergyAustralia Stadium.

In the most dramatic match of the season, former international winger Adam MacDougall completed a "special" tryscoring hat-trick with just 30 seconds left on the clock to set the scene for Johns' latest act of heroism.

Two nights ago, the brilliant halfback scored a try, set up three others, landed four conversions from four attempts, slotted a field goal, tackled his heart out and generally mesmerised Queensland to lead NSW to its 25-12 victory in State of Origin I.

So his sideline winner tonight hardly came as a surprise to Hagan, who said with a wry smile "we were fairly hopeful he would kick it".

"You do run out of superlatives - genius springs to mind," Hagan said after Johns was presented with a centenary medal to recognise his 201 games for the Knights.

"It was a pretty fair end to the script for Andrew over the last couple of weeks. I think he has achieved quite a bit in the last fortnight.

"It was another memorable moment in his career.

"I'm surprised he had enough energy to kick the goal. He and the other boys who backed up (from Origin) were exhausted after the game, physically and emotionally."

A delighted MacDougall described his hat-trick as special after spending the last 14 months on the sidelines with a knee injury.

"But I'm just glad I got through the game without injury. That's the main thing," he said.

While Newcastle - and Johns and MacDougall in particular - were lapping up all the plaudits after the Knights' great escape, the Dragons were still wondering how they lost.

"It was a hard loss. My blokes are shattered," St George Illawarra coach Nathan Brown said.

Tryscoring freak Nathan Blacklock, who like MacDougall was playing his first NRL match in more than a year, was so nearly the hero for St George Illawarra, having crossed for a first-half double to give the Dragons a handy 18-6 lead.

But three tries in six minutes straight after the break and MacDougall's hat-trick, two of which were set up by NSW hooker Danny Buderus, vaulted Newcastle back into the lead.

However, just as the Knights seemed set to go further ahead as they attacked the St George Illawarra line feverishly on the last tackle, Newcastle winger Timana Tahu threw an intercept pass to Dragons centre Matt Cooper, who sprinted nearly the length of the field to score under the posts.

Replacement hooker Mark Riddell's conversion made it 24-22 to the Dragons.

Buderus was held up over the line on the hour mark and then Dragons prop Jason Ryles, a dramatic late starter after withdrawing yesterday with a shoulder injury, pounced on a Dean Byrne kick to score.

Riddell again slotted the conversion and the Dragons appeared set for victory leading 30-22 with 13 minutes remaining.

But MacDougall's second four-pointer of the night gave the Knights hope - again - before "Mad Dog" sent the home crowd of almost 20,000 into a frenzy when he completed his hat-trick with 30 seconds left on the clock.

The fabulous victory came at a cost for Newcastle.

Young second rower Clint Newton was stretchered off in the second half with a season-ending ankle fracture, while prop Josh Perry was placed on report in the second minute of an eventful first half for an elbow to the head of Dragons captain Lance Thompson.

Perry has already been suspended this season for face-raking Wests Tigers veteran Terry Hill.

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