Ulster came from 23 points behind to claim victory
Oyonnax - 23
Ulster - 24
Paddy Jackson's incredible kick from within his own half completed a stunning comeback for Ulster as they keep their European ambitions alive as the sole province flying the Irish flag in the Champions Cup.
It was the second half double act of Jackson and Ruan Pienaar that swung the game back in Ulster's favour with Rory Scholes, Craig Gilroy and Kyle McCall touching down before Jackson's late heroics.
Ulster were in real danger of becoming the latest Irish province to fall at the Pool stages of Europe after 40 minutes when they trailed by 23 points, but Les Kiss brought on a number of frontliners including the half-back switch and Louis Ludik, to rescue the game.
A blistering start from the French side gave them a 10-0 lead in the opening exchanges, with hooker Jeremie Maurouard touching down from the back of a rampaging Oyonnax maul inside the opening few minutes.
Nicky Robinson gave a masterclass outhalf display in the first half and added his first penalty after Maurouard's break and his own grubber in behind gave Oyonnax field position immediately after the try, and Ulster were happy to concede three points.
Robinson then extended the lead with another penalty to keep the scoreboard ticking over, rewarding them for their incredible attacking intensity in the first half.
Oyonnax obliterated the Ulster scrum on a number of occasions, but doing so twice in the space of two minutes on Ulsters own put in lead to another Robinson penalty to put 16 between them.
Ulster went in search of a score before half time, twice visiting the 22' and coming away with nothing after fantastic defence which saw Gilroy knock-on in the the tackle before Robbie Diack had the ball stripped from his grasp as he charged for the line.
Then a pivotal moment in the game came as Ulster were attacking deep in the Oyonnax 22', Paul Marshall sent out out a loose pass which was scooped up by Uwa Tawalo who outpaced the minimal Ulster cover to touch down under the posts.
Robinson's conversion took his tally to 13 points for the first half in a masterclass display and left Ulster with a mountain to climb at the interval.
However, with the added reinforcements on the pitch for Ulster led by their new half-back duo, they were a different.
The changes had an immediate effect, adding a different dynamic in attack, but it was Rory Scholes who raced over with a magnificently finished try as he received McCloskey's reverse pass to find the gap before dancing away from four desperate last ditch tackles to score . Jackson converted and it was game on.
They soon added a second after Rory Scholes big hit forced a penalty from a Pienaar box kick, and the Springbok went quickly down the left before Ulster showed good hands to spread it wide and see Gilroy finish in the corner.
Jackson converted again and the Ulster's tails were up but Oyonnax defended admirably for large portions of the half, repelling multiple assaults on their line until they couldn't hold firm any longer.
It was made a two point game after the Northern province forced a knock-on from Oyonnax inside their own 22', allowing them to attack from the scrum. Quick clear outs and quick ball was the order as Kyle McCall dove over with the French sides defence stretched.
It was a tense finish both sides with defensive discipline required, but Oyonnax couldn't hold their nerve and up stepped Paddy Jackson to send the Ravenhill faithful into delirium.
There was time for one last twist and it almost came when Oyonnax earned a scrum on close to the posts, but there was to be no denying Ulster an historic victory.
One final scrum had Ulster hearts in mouths but they withstood and claimed victory.