George Hendy produced some second-half heroics to help Saints get over the line in their Investec Champions Cup opener on Sunday evening.

Hendy scored a crucial second-half try with his team down to 14 men as Anthony Belleau had been sin-binned just before Cardiff cut the gap to two points.

And another big contribution from Hendy helped Saints to keep the breathing space he had given them as he raced back to make an incredible try-saving tackle on Josh Adams.

A fantastic finish from club captain Fraser Dingwall finally made the game safe on a night when Saints were made to work hard for their 28-12 win.

It was a largely fragmented game at DPD Stadium at Franklin's Gardens, owing much to the heavy rain that fell during the first half, making handling so tough.

It stopped Saints, who had made seven changes to the team that had bagged a brilliant 71-48 win against Bath eight days earlier, ever really getting into their flow.

But the key thing was that they claimed the victory in a competition where the margin for error is so small.

The rain had poured down at the Gardens ahead of kick-off, making the opening stages of the match pretty precarious as both sides struggled to handle the ball.

Cardiff dominated the early possession but they were met by a wall of Saints defence, which kept the Welsh side at arm's length close to halfway.

And when Saints got the chance to pounce, they took it with ruthless efficiency as Hendy, so sharp in the opening stages, led a break before giving the ball to Alex Mitchell, who fired a fine pass inside for the onrushing James Pater to finish in strong fashion.

Belleau converted and Saints led 7-0, having not been in the Cardiff 22 prior to their 12th-minute try.

It was turning into a truly chaotic affair due to the conditions and the decision-making that the rain was prompting, but Saints were so sharp when they got their chance to punish Cardiff.

After Mason Grady took the ball back over his own try line, Saints earned a scrum free-kick, allowing them to work the ball to Toby Thame, who finished in powerful fashion.

Belleau easily added the extras to put his team 14-0 up and Saints had the chance to really turn the screw after winning a penalty inside the Cardiff half, but Belleau missed touch.

Cardiff were straight at the home door, but they could not find a way through the resilient Saints defence, with the hosts able to escape after their opponents lost a lineout.

Danilo Fischetti did some great work to kick ahead and chase down a Cardiff defender inside the away 22, earning Saints a penalty.

And the black, green and gold came so close to scoring as Callum Chick was just millimeters from getting the ball down on the Cardiff line.

Cardiff needed a way out and they eventually managed to work their way back downfield, with Mason Grady delivering an impressive run that was eventually halted by Ollie Sleightholme.

However, Cardiff were able to recycle the ball and Leicester loanee Tom Manz looked to have scored, but the TMO spotted he had lost possession over the line and it was a goal-line drop-out for Saints.

Manz had to go off for a head injury assessment, making it a double blow for the lock and Cardiff, though he did eventually return to the field.

The Welsh side had another chance to score before the break, but their faltering lineout cost them possession in the Saints 22 once again.

Cardiff remained on the front foot at the start of the second half, and they finally got over the line when centre Harri Millard powered over after his side had taken a tap penalty close to the home line.

Jarrod Evans converted and Saints really needed some sort of spark as Cardiff's confidence continued to grow.

Saints were really struggling to get anything going in such slippery conditions against a determined Cardiff rearguard.

The hosts looked to have a chance to strike from a lineout close to the Cardiff line, but the away side again stood tall, refusing to let Saints through as they lost their chance.

Saints sent on Archie McParland and Fraser Dingwall in search of a lift, but Cardiff were refusing to shift and they sensed an upset at just seven points down with 20 minutes to go.

The Cardiff confidence was through the roof when Belleau was sent to the sin bin for hands in the ruck with his side again under huge pressure inside their own 22.

Cardiff immediately made Belleau and Saints pay as Grady went over on the right.

Evans had the chance to level the scores with the conversion on the touchline but he missed it under huge pressure from Sleightholme, who had raced out to try to charge it down.

The home supporters knew their team needed help, lifting the noise levels and helping the black, green and gold to lift their performance levels.

Saints responded well to the setback as Hendy juggled the ball and made his way over the line to grab a vital score for his 14-man side.

With Belleau in the sin bin, Pater converted, making it 21-12 with 15 minutes remaining.

Hendy then did some incredible work at the other end of the field as he raced back to somehow bundle Adams into touch when the wing looked certain to score.

Saints were eager to finally finish the game off, and they did that when Belleau's big run pushed Cardiff back, with Charlie Ulcoq finding a nice pass for Dingwall, who somehow kept his feet and ran in under some pressure from the edge of the away 22.

Belleau converted well and Saints had a few seconds to seek a try that would have given them a try bonus point.

However, Cardiff kept the hosts in their own half and brought an end to the game as the ball was lost, as it so often had been on a rain-soaked night at the Gardens.

Saints: 15 James Pater (Fin Smith 70); 14 Ollie Sleightholme, 13 Rory Hutchinson, 12 Toby Thame (Fraser Dingwall 57), 11 George Hendy; 10 Anthony Belleau, 9 Alex Mitchell (Archie McParland 57); 1 Danilo Fischetti (Jordan Els 62), 2 Robbie Smith (Curtis Langdon 62), 3 Cleopas Kundiona (Ion Neculai 53); 4 Tom Lockett, 5 JJ Van Der Mescht (Ed Prowse 53); 6 Josh Kemeny, 7 Josh Taylor (Charlie Ulcoq 67), 8 Callum Chick (c).

Cardiff Rugby: 15 Matty Young; 14 Mason Grady, 13 Harri Millard (Josh Adams 57), 12 Steffan Emanuel; 11 Tom Bowen; 10 Jarrod Evans (Callum Sheedy 62), 9 Johan Mulder (Sion Davies 77); 1 Danny Southworth (Rhys Barratt 56), 2 Daf Hughes (c) (Evan Lloyd 57), 3 Sam Wainwright (Joe Cowell 65); 4 Tom Manz (Josh McNally 72), 5 Rory Thornton; 6 Semisi Paea (Lucas De La Rua 62), 7 Dan Thomas, 8 Taulupe Faletau.

Referee: Jeremy Rozier (France)