Saints complete one of the great comebacks to book Challenge Cup quarter-final spot

Taqele Naiyaravoro scored for Saints during the first half at Rodney Parade

Chris Boyd's side were 22-3, 32-17 and 39-24 down at Rodney Parade, having been hit with three yellow cards along the way.

But they showed a gargantuan amount of character to roar back into contention late on, and a sensational breakaway score from Tom Collins sealed a surreal 43-39 win.

It means Saints will now look forward to facing the winners of Harlequins' last-16 encounter with Ulster at Franklin's Gardens next Saturday.

Fraser Dingwall was in action against the Dragons

And the black, green and gold did it all without a laundry list of key men, including Courtney Lawes, David Ribbans and Dan Biggar.

Not only that, but they lost Nick Isiekwe before kick-off in Newport as he was forced to miss out with a neck injury, bringing Shaun Adendorff into the back row at seven.

And the away pack was put under early pressure at scrum time, with the Dragons earning a penalty that allowed Sam Davies to put his side in front.

It soon got worse for Saints as the home side pieced together a lovely move, which included a brilliant pass from Rhodri Williams and a tidy kick from Jamie Roberts, allowing wing Ashton Hewitt to race forward and dot the ball down in the corner.

Ollie Sleightholme was sin-binned in the first half but scored a superb try in the second

Davies added the extras and Saints were 10-0 down after just 12 minutes.

The black, green and gold were really struggling to get a foothold in the game, with their lineout barely functioning at all in the formative stages.

But when Saints did manage to pouch a throw, they set up a move that forced Dragons to offend, giving James Grayson an easy three points from the tee.

However, Saints were down to 14 almost immediately as Ollie Sleightholme was sin-binned for pulling back Williams off the ball.

Dragons scored a try at the end of that move, with Matthew Screech the man on the mark.

Davies converted to make it 17-3 and it was already a long way back for Saints after 25 minutes.

It was error after error for the away side, who were losing lineouts with alarming regularity and who were also having a tough time at the scrum.

Dragons soon made them pay again, using a dominant lineout drive to gain ground before the ball was sent left for Hewitt to score in the corner.

The wing was injured in the act, being forced off, but he could at least enjoy the fact he had two tries to his name.

Saints were desperate to respond before half-time, and they did so through one of their own wingers, as Taqele Naiyaravoro picked up from the breakdown and glided through a gap to score.

It was great awareness, and Grayson's conversion cut the gap to 12 points with just a few minutes to go until half-time.

Saints came out firing at the start of the second period, scoring inside a minute as Naiyaravoro made a break, Mitchell kicked ahead and Sleightholme finished with incredible balance and poise in the corner.

Grayson landed the conversion well, and Saints were suddenly just five points down.

Dragons issued an immediate riposte thanks to the boot of Davies, and the home side continued on the front foot, forcing Alex Coles and JJ Tonks into the sin bin during the same move.

And Saints couldn't hold out as Davies darted inside to score after the Dragons moved the ball left from a scrum.

Davies also converted to make it 32-17 with 28 minutes to go.

But Saints wouldn't go quietly and the 13 men scored again after Naiyaravoro carried well, allowing Mitchell to pick up. The scrum-half turned on the turbos and went round the Dragons defence to grab a quite superb try.

Grayson converted well again before Saints returned to a full complement but still the indiscipline continued from the away side, who received another warning from the referee.

And Dragons soon scored again, with replacement prop Leon Brown powering over.

Davies converted again and Saints were 15 points down with 19 minutes to go.

But again the away side responded, with a fine move resulting in great work from Ahsee Tuala setting up Teimana Harrison in the corner.

Grayson missed the conversion to leave Saints 10 points down with 16 minutes to play.

Saints started to build pressure and Dragons hooker Elliot Dee was sin-binned with nine minutes remaining.

Saints frantically tried to get over the line, and they did so when Collins sent a long pass to the left for Naiyaravoro to go over unopposed.

Grayson converted to reduce the deficit to just three points with six minutes to play, and Saints scored again almost immediately thanks to some brilliance from Henry Taylor and Collins.

Taylor broke away and kicked into a perfect area for the onrushing Collins, who kicked and then grounded the ball.

Grayson converted and Saints led 43-39 with four minutes to go.

And when the Dragons knocked on with the clock in the red, Boyd's side could celebrate the most incredible of wins.

Dragons: J Williams, Holmes, Owen, Roberts, Hewitt (Tompkins 34), S Davies, R Williams (c) (Bertranou 58), Bateman (Reynolds 68), Dee, Fairbrother (Brown 58), Davies, Screech, Wainwright, Keddie (Baker 68), Moriarty.

Saints: Mallinder (Tuala 56); Sleightholme (Collins 59), Dingwall, Hutchinson, Naiyaravoro; Grayson, Mitchell (Taylor 69); Auterac (Waller 57), Haywood (Fish 52), Painter (Heffernan; Moon, Coles; Tonks, Adendorff (Matavesi 68), Harrison (c).

Referee: Alexandre Ruiz (France)