Played in damp and cold conditions, the Broncos were the first score through backrower Corey Parker after just five minutes. A high kick from Darren Lockyer and fumble from winger Ade Gardner presented the try to give the Broncos an early lead.
Parker slotted a penalty goal soon after to put the visitors ahead by 8-0.
St Helens plied on the presssure in the first half before Gardner finally cracked the line just before the break. Paul Sculthorpe's sideline conversion put the locals just two points behind.
At half time, the Broncos held a tenuous 8-6 lead.
The Broncos came out firing in the second half and extended their lead through winger Darius Boyd following a cross field kick from Darren Lockyer. The try was marred by a blatant forward pass a couple of plays earlier and missed by Referee Steve Clark.
But St Helens were not to be denied. Paul Sculthorpe [pictured] celebrated his return from injury with a try in the 56th minute. His conversion from almost in front locked the scores up at 12-all.
Another Parker penalty goal in the 62nd minute put the Broncos back in the lead but it was the home side who were gaining the ascendancy.
First half villain Ade Gardner redeemed himself in total when he scored the winning try in the 70th minute.
St Helens 18 Tries: A Gardner 2, P Sculthorpe Goals: P Sculthorpe 3/3 defeated Brisbane Broncos 14 Tries: C Parker, D Boyd Goals: C Parker 3/4
Reebok Stadium, Bolton Referee: Steve Clark (Aus) Crowd: 23,207
5 min: TRY BRONCOS: Corey Parker regathers a loose ball and scores. Follows video ref scrutiny for possible offside and knock-on. CONVERSION: Parker converts. Broncos 6-0
12 min: PENALTY GOAL BRONCOS: Matt Gidley penalised for lifting in the tackle. Parker slots the goal. Broncos 8-0
39 min: TRY SAINTS: Ade Gardner in the corner on the back of enterprising backline movement. CONVERSION: Paul Sculthorpe brings the house down with a tremendous conversion. Broncos 8-6
HALF TIME: Broncos 8-6
42 min: TRY BRONCOS: Cross field kick from Darren Lockyer marked by Darius Boyd. MISSED CONVERSION: Corey Parker 15m wide of the goal is unable to convert. A blatant forward pass from Shane Perry a couple of plays earlier was missed by referee Clark. Broncos 12-6
56 min: TRY SAINTS: Sculthorpe hits the gap and crashes over following a deft pass from Keiron Cunningham close to the line. CONVERSION: Sculthorpe converts from almost in front, and its all locked up. 12-all
45 min: NO TRY: Broncos denied following a scramble for a loose ball. Video ref deems that Lockyer knocked on before Parker touched down.
62 min: PENALTY GOAL BRONCOS: Broncos get the penalty following high tackle on Dane Carlaw by Matt Gidley. Parker is successful from 24m out and almost in front. Broncos 14-12
70 min: TRY SAINTS: Gardner totally redeems himself with a high leap following a cross field kick from Sean Long. Gardner goes up first, gets to the ball first and comes down to score wide of the uprights. CONVERSION: Sculthorpe converts and St Helens hit the front. Saints 18-14
FULL TIME: Saints 18 - Broncos 14 St Helens control play in the final minutes to cap off a tremendous 2006-2007, adding the World Club Challenge to their trophy cabinet.
St Helens: Paul Wellens, Ade Gardner, Matt Gidley, Willie Talau, Frances Meli, Leon Pryce, Sean Long, Nick Fozzard, James Roby, Jason Cayless, Lee Gilmour, Mike Bennett, Jon Wilkin. Interchange: Paul Sculthorpe, James Graham, Bryn Hargreaves, Keiron Cunningham.
Brisbane Broncos: Karmichael Hunt, Darius Boyd, Brent Tate, Justin Hodges, Steve Michaels, Darren Lockyer (c), Shane Perry, Dane Carlaw, Shaun Berrigan, Petero Civoniceva, Corey Parker, Brad Thorn, Tonie Carroll. Interchange: Sam Thaiday, Greg Eastwood, Ben Hannant, Nick Emmett.