Gidley's winning kick, from 32-metres out, never looked good off the boot but had enough on it to scrape over the cross bar and deliver a thrilling win to the visitors.
Following a tremendous first half of NRL football, the Knights were hanging onto 10-4 lead before the Broncos came back in the second half.
The Broncos hit the lead in the following a try Michael De Vere and with a little over ten minutes remaining, the home side held a 16-10 lead.
But the Knights struck back with a try to Danny Buderus in the 72nd minute.
Both sides desperately tried to break the deadlock but after 80 minutes, the scores were locked up at 16-all.
The resumption of play saw two exhausted teams take up their positions before Kurt Gidley kicked the golden point after 3 minutes of extra time.
The win may have come at a price for the Knights with prop Josh Perry was placed on report for a high tackle on Ben Ikin in the first half. Also in the first half, skipper Ben Kennedy suffered another hamstring injury.
BRONCOS 16 Tries: Frawley, Hunt, DeVere Goals: DeVere 2/3 defeated by KNIGHTS 17 Tries: Hall 2, Buderus Goals: K Gidley 2/3 Field Goal: K Gidley
Suncorp Stadium Referee: Paul Simpkins Video Referee: Tim Mander. Touch Judges: Matt Cecchin, Steve Carrall
By the clock: by Tim Lawrence Round 10 is almost under way as the Broncos will do battle with the Knights at Suncorp Stadium. Ben Ikin replaces Shaun Berrigan in the run on side for the Broncos. The Knights are as per progamme. Conditions are fine.
0 min: The Knights kick off.
2 min: News - Following a penalty the Knights run the ball hard. Kurt Gidley puts in a superb grubber as the Knights force the Broncos in-goal.
4 min: News - After the Knights force the Broncos in goal they drop the goal from the goal-line drop out
6 min: Try-Brisbane: Following a penalty the Broncos pass it out wide. A beautifull pass by Karmichael Hunt finds a flying Craig Frawley to score out wide. DeVere's conversion attempt goes wide. 4-0 Brisbane
9 min: News - Newcastle's fullback Mark Hughes comes off the field with a hamstring injury.
13 min: News - Josh Perry is on report for a high tackle on Ben Ikin.
18 min: News - On the last tackle the Knights put in a grubber. It's far too strong.
19 min: News - Craig Frawley comes close to scoring but is held up,A knights player touched the ball before hand so the Broncos get another set.
19 min: News - Ben Kennedy is off the field and could be out for the rest of the match with an injury.
20 min: News - The Knights are too strong on defence near there own line as the Broncos are tackled on the 6th tackle.
21 min: News - Craig Hall makes a big break but is tackled by Broncos fullback Karmichael Hunt. The Knights then throw the ball around until Tonie Carroll intercepts a Newcastle offload 5 metres out.
23 min: News - The Knights get another set of six after Brent Tate batters the ball over the dead ball line after a Knights grubber.
31 min: News - After Gordon Tallis was held up and another set of six Broncos rake Michael Ryan is ruled to have done a double movement after he was tackled and rolled over to plant the ball on the line.Replays showed he was hard done by.
33 min: News - Karmichael Hunt shows his class as he kicked and re-gathers. He beat one man then passed to an un-marked Broncos player who dropped the ball so close to the line.
35 min: News - Ben Ikin puts up a bomb to the left side of the field. Craig Frawley grabs it but knocks it on in mid air.
37 min: News - Two superb breaks almost lead to a Broncos try all in one set. The Broncos get another set with 3 minutes to halftime.
38 min: News - Broncos fullback Karmichael Hunt shows he is human after all after dropping the ball in excellent territory.
40 min: Try-Newcastle: The Knights spread the ball from a scrum. George Carmont attracts two defenders then passes it to a flying Craig Hall on the flank who runs 70 metres to score on the buzzer,superb stuff.Kurt Gidley converts.
Halftime: Newcastle Knights 10 are leading the Brisbane Broncos 4. The Broncos are unlucky not to have scored more but give full credit to this Knights outfit,theyve defended well and have looked excellent in patches with the ball. A superb 40 minutes of football has come to an end. Halftime stats: Penalties:4-2 Knights Mistackles:13-8 Broncos Linebreaks:4-3 Broncos Sets and completions: Broncos 16/21 (76%), Knights 16/22 (72%)
40 min: The Broncos re-start the match.
43 min: News - After George Carmont was held up over the line the Knights get another set of six.
44 min: News - The Knights spread the ball,a pass goes wayward and a flying Craig Frawley drops the ball trying to regather it.
45 min: News - The Broncos force a Knights player over the sideline.A good show of strength.
48 min: News - A text book perfect play almost pays off for the Broncos after Craig Frawley over runs the last pass.
52 min: Try-Brisbane: Broncos utility Casey McGuire breaks through several Knights players passing it to Karmichael Hunt who was outside him to score.Michael DeVere's conversion is succsessful.10-10
56 min: News - Following a Craig Frawley break and a penalty near the line the Broncos spread the ball,Craig Frawley looks like he's about to score but is tackled by a Knights player.He offloads the ball but is then knocked on by Brisbane centre Brent Tate.
58 min: News - A high kick is put up by Ben Ikin,with no pressure on him Matt Gidley makes a simple error.
59 min: News - The Brisbane faithfull blow up at referee Paul Simpkins after it appeard that Danny Buderus kicked the ball from the play by ball area,winger Stuart Kelly dives on the ball and the Knights get possesion of the ball as it was the last tackle.
63 min: News - The Broncos force Anthony Quinn in goal to get another set of six. Some of the Newcastle forwards must be getting tired by now.
67 min: Try-Brisbane: On the last tackle The Broncos put up a bomb to the left side of the field. Craig Frawley batters it back and is then picked up by Brent Tate-he offloads it on the ground,Ben Ikin then gets the ball and throws a basketball pass over the head of two knights players to find Michael DeVere who scores. DeVere converts his try. 16-10 Brisbane
67 min: News - More pressure is yet to applied to the Knights after a grubber into the in goal area is simply run out by Matt Gidley.
68 min: News - Neville Costigan throws an outstanding offload pass to a unmarked Craig Frawley who knocks the ball on. The Knights fight to live another day.
73 min: News - George Carmont slices through the Broncos defence,He passes to Steve Witt whos outside but he's tackled around the ankles and drops the ball so close to the line. Full time: 16-all and extra time.
83 min: Field goal - Knights. Kurt Gidley kicks the golden point from 32m out and the Knights are victorious 17-16
Leagueunlimited.com players of the match: 3 - D Buderus (Knights) 2 - K Gidley (Knights) 1 - K Hunt (Broncos)