Under gigantic pressure from four-time winner Jamie Whincup (partnered by Paul Dumbrell), Winterbottom finished less than a second ahead, with Red Bull's Lowndes/Luff pairing in a hard-fought third place.
European drivers Andy Priaulx and Mattias Ekstrom were the stars of the race, the wildcard Triple 8 entry finishing tenth.
The number 1 Red Bull Racing Commodore, with Paul Dumbrell at the wheel, got a fantastic start, pulling out three car lengths on Bright's BOC VF by the first corner. The start was otherwise uneventful, apart from Winterbottom's poor start and a slow starting car down the pack.
Winterbottom lost six places while Garth Tander tried to make up places in turn two heading up the hill. Greg Murphy started in Courtney's HRT and was immediately under sustained attack from Scott McLaughlin's GRM VF.
As the race settled, the FPR cars latched on to the tail of McLaughlin's GRM which was being held up by Greg Murphy in the HRT. All three got past on lap 11, with McLaughlin setting off after van Gisbergen's VF.
It was a clean, uneventful motor race until lap 86 when Greg Murphy had a nasty shunt at Reid Park. He ran wide, lost the car on the marbles at 175km/h and cannoned into the wall on the outside of the circuit.
The front left was torn off and the car crabbed to a stop, a contrite Murphy immediately on the radio to apologise. Bathurst can be cruel and unforgiving: while not a front-runner, the car had run well in both his and Courtney's hands.
After the pit stop cycle had completed, Winterbottom's Falcon emerged in the lead, closely followed by the Whincup Commodore. The Winterbottom car pitted on the same lap as Lowndes, leaving Whincup to the lead.
Whincup came in on the next lap, the FPR team's strategy to stay in front with the F1-style 'undercut' working to perfection, the two cars running fourth and fifth. Jason Bright's Team BOC Commodore was third.
The pack held their collective breath after Michael Caruso's Nissan V8seemingly exploded on the way up the mountain. The Altima made it back to the pits without the need for a safety car. It was later found to have been a problem with the power steering.
Ekstrom was returned to the lead on lap 126 after HRT's Tander/Percat entry returned to the pits. It was a stunning result after starting so far back and without the assistance of the usual torrent of safety cars.
The racing began to heat up in the last forty laps. The vast majority of the field was still on the road and Lowndes began to attack Jason Bright's Team BOC, almost passing on lap 129 at the final corner.
Ekstrom eked out a longer lead at the front, lapping faster than any of those behind him, so the team left him out as long as they could.
The clouds arrived over the circuit on lap 137, dropping the temperatures and changing the wind direction, meaning the drivers were driving on a completely different circuit to the one they had started on.
Whincup pitted on lap 139 for what the team hoped was his final stop for brake pads and fuel. The car was sent out as Winterbottom and Lowndes pitted. Lowndes had clouted the wall at Forrest Elbow and as he sat in pitlane, Whincup's car was spewing fuel on the way to turn two.
Whincup mounted his first major attack on Winterbottom on lap 142, with Bright right on his tail.
The new tyres and pads had clearly filled the championship leader with confidence he'd not had in the previous stint.
Lowndes began to close on lap 143 as the end of the race turned into a full-on sprint after almost six hours of racing. The weather was threatening enough for the teams to begin preparing wet weather tyres.
Bright had a tank full of fuel and was authorised to charge as hard as he wanted.
Tander exited the pits behind Craig Lowndes, putting him in fifth and with a tow from the hard-charging 888 of Lowndes.
As Whincup faltered, Lowndes again attacked with the fastest lap on the race on lap 146, putting him two seconds behind Bright and four seconds from the overall lead, at which he chipped away over the next few laps.
Bright responded with fastest sectors to try to keep Lowndes at bay and to mount pressure on Whincup. It was to no avail as Lowndes reached his bootlid on lap 148, with Tander in tow.
Tander threatened over the top of the mountain but Lowndes remained fixed to Bright's rear bumper. On lap 150 Tander nearly ended it all as he tried to nose ahead of Lowndes, again at the top of the Mountain.
Lowndes had to pass Bright to shake off Tander to have any hope of catching the leaders and get on the podium. Tander took the risk on lap 151 at turn three, forcing Lowndes on to the marbles and passing cleanly.
Tander pressured Bright straight away, spending little time behind the BOC Commodore and took the position but only momentarily. Tander's pace was compromised, and Lowndes was able to muscle past after watching Tander and Bright go side by side through three corners.
Tander held his nerve at turn two, however and kept it on the road to get the place back. This battle brought David Reynolds ever closer. Bright also got some breathing space as Tander and Lowndes squabbled.
On lap 155, Bright had a couple of tiny lock-ups, giving Tander yet another opportunity to pass at the end of the Chase. He filled Bright's mirror s across the top of the mountain the follow lap, again trying to pressure Bright into a mistake.
At the front, the battle was tense as Winterbottom and Whincup traded faster times, but it was much calmer than the battle behind.
Tander took the dive on lap 157, but both went too deep and off the road. Lowndes didn't need a second look and shot past them both to take third, Tander resuming the track in front of a deeply unimpressed Bright.
Bright then went wide at turn two, with Reynolds passing him as he tried to stay off the fence. Tander wasn't done yet, and resumed battle with Lowndes.
Whincup was chucking everything at Winterbottom, the four-time winner sliding around as he attacked and dived where he could. Winterbottom had never won at Bathurst but was implacably calm.
The final lap began with Winterbottom in front by the smallest of margins. Winterbottom blocked Whincup's attack at turn two by taking the middle of the track. Whincup had one move to make and he made it there.
The FPR car was in the way though, and Whincup went wide into the marbles, trying to get around the outside. Winterbottom's bravery served him well and he had the win. Whincup came back as close as he could, but it was done.
Lowndes came home third, with Tander fourth and a still-unhappy Bright fifth.
The third endurance race of the season kicks off at the Gold Coast 600 on October 25.
Note: further photography to be added as images become available.