Tries from Cameron Winnett, James Botham and Theo Cabango were not enough as a second-half surge from Harlequins inflicted a Heineken Champions Cup defeat on Cardiff.

For a second week in a row, the Blue and Blacks were without more than 40 first team regulars but the club did it’s all the fulfil the fixture as so many others fell.

Once again it was an almost insurmountable challenge, away to the English champions, but Cardiff will leave the Stoop with nothing but pride following another unbelievable effort in the face of adversity.

With a team of few regulars and a host of academy starlets and semi-professional stalwarts, they gave their absolute all once more and entered half-time level.

They were in dreamland as 18-year-old debutant Winnett flashed over for the game’s opening try but there was so much more to come.

James Botham powered over before Theo Cabango dazzled with an electric finish to send the away support into euphoric celebrations.

They dominated the opening quarter of the second-half but were unable to grab a fourth try before full-strength Harlequins showed their champion credentials in the final 20 minutes.

The hosts racked up racked up 26-unanswered points as Alex Dombrandt (2), Joe Marchant and Andre Esterhuizen to add to Danny Care and Marcus Smith’s earlier efforts.

Cardiff now return to United Rugby Championship action, and on Monday will be boosted by the 32 players, who have been stuck in quarantine for so long.

James Botham set the tone early in the defence, with a thumping hit on the charging Alex Dombrandt in midfield. The challenge caused a halt in the Quins’ momentum and a knock-on out wide was picked up by Seb Davies.

Soft hands by the lock found Dan Fish in support, who kicked ahead into space, but Josh Adams was beaten to the loose possession by his opposite man.

The visitors remained on the front foot in the opening five minutes, and duly opened the scoring after Danny Care was penalised for offside.

Carries by Sam Moore and Ellis Jenkins made a dent in the home defence before Fish shipped wide to debutant Winnett.

With Adams in support, the full back – who had played under-18 rugby for the club back in June – had plenty to do, but squeezed through the make it a dream start on his debut.

However, the defending English champions responded immediately following the restart.

Despite some excellent defensive reads by Adams, almost certainly denying two tries, they continued to attack and were duly rewarded for their pressure.

Once more they threatened down the left and the numbers eventually told as Jack Kenningham released Danny Care on the inside, with the scrum half sliding in unopposed.

Marcus Smith’s conversion brought proceedings level, but there was a double blow for the Blue and Blacks as British and Irish Lion, Adams, was sent to the sin-bin after up-ending Tyrone Green earlier in the attack.

Despite the man disadvantage, the visitors regained the lead as they continued to pile the pressure on Harlequins.

When the hosts were penalised at scrum time inside their 22, a quick tap caught the English champions napping, allowing James Botham to power over from short range.

The end-to-end rugby continued to warm the Twickenham Stoop crowd, as the home side replied once again.

This time it was Smith who provided the spark, breaking clear in midfield before interchanging passes with Dombrandt and diving in under the sticks – despite the admirable chase from Botham and Lee-Lo.

Converting his own effort, Smith put Harlequins ahead for the first time and added a further three after Fish strayed offside in midfield.

England duo Joe Marchant and Dombrandt combined to put Cadan Murley in acres of space in the left, and a third try seemed inevitable. But an immense cover tackle by Sam Moore denied the wing and drew a penalty from the breakdown.

With five minutes remaining in the half, Cardiff pulled level with a stunning score of their own. Skipper Jenkins won the turnover on half way, and a brilliant offload by lock Davies gave Cabango the space to stretch his legs.

He pinned his ears back, beating three defenders and finishing brilliantly out wide and claim his first try for the Blue and Blacks.

A 50:22 by Winnett almost paved the way for a quickfire second for Cabango.

After winning the line-out and going through the phases, Winnett once again nudged the ball through, but this time Cabango was beaten to the possession by the dead ball line.

The teams went into the changing rooms all level at the break, but Cardiff came out firing after the restart.

Wing Adams continually threatened down the right, combining well with both Lee-Lo and Halaholo.

And it looked like the hosts finally had the breakthrough for the bonus point as the Lion powered over, but he was agonisingly held up over the whitewash.

After dominating the opening 10 minutes of the second half, Cardiff lost captain Jenkins as a blood replacement, with Wales under-20 skipper Alex Mann introduced for his senior debut.

A couple of penalties saw Quins gathering momentum and territory, and they showed their clinical edge, crossing with their first opportunity of the half.

Former Cardiff Met number eight, Dombrandt, was the one who pummelled over as the hosts took the lead heading into the final quarter.

Marchant latched onto a Smith crossfield kick moments later to take Harlequins further ahead, injecting further momentum into the hosts.

Dombrandt soon added his second – and the Quins’ fifth – to open up a 19-point difference.

Cardiff continued to battle admirably, with Cabango’s pace continuing to cause problems for the English champions.

A late hit on Fish – whose performance was causing plenty of waves on social media and at The Stoop – gave Cardiff another opportunity in the 22, and it looked like they had the bonus point sealed.

A trademark Tomos Williams chip behind saw Tyrone Green and Lee-Lo going head-to-head for the loose ball. The ball fell kindly to lock Davies who dotted down, but the TMO chalked it off after controversially judging it to be a knock on by the Samoan centre.

Esterhuizen rubbed salt into Cardiff’s wounds with two minutes to go and Louis Lynagh had a breakaway at the death ruled out.

However, once again the result was overshadowed by the remarkable, spirited effort from Gruff Rees’ misfit group.