Cardiff crashed to their heaviest European defeat in 17 years as they were outclassed by five-time champions Toulouse in the Investec Champions Cup.

Wales Under-20s number eight Mackenzie Martin claimed his first senior try in a spirited display.

But a young Cardiff side struggled to match the firepower of their hosts.

Matthis Lebel, Richie Arnold, Kinghorn and Anthony Jelonch wrapped up a bonus point by half-time before Arthur Retiere, Alban Placines and Kinghorn - with the final attack - completed the rout.

Yet Toulouse rarely got out of third gear in what was a repeat of the first European Cup final 27 years ago.

It was the new generation of stars that pulled the strings for Toulouse, with fly-half Thomas Ramos the only player who could have outshone Antoine Dupont for man of the match.

Cardiff, to their credit, played with pace and ambition, turning down early shots at goal. But they failed to capitalise on a share of possession that many teams struggle for in Toulouse.

The French side may be stuttering in the Top 14 but their unbeaten home run that stretches back to February 2022 never looked under threat once they were two tries up inside 10 minutes.

Lebel squeezed over in the left corner after Toulouse's backs kept the ball alive, before the wing turned provider for lock Arnold.

Time and again Cardiff worked their way into the Toulouse 22-metre line, but hooker Efan Daniel was held up over the line before number eight Martin powered over on 23 minutes.

The 20-year-old was part of a youthful back row, alongside teenager Lucas de la Rua on his first start, but picked his line to barge over for his first senior try.

But Toulouse struck back immediately when Ramos fended off Josh Adams with ease and Dupont sent Kinghorn over for a debut try.

Cardiff continued to create chances that went unfinished. Fly-half Tinus de Beer broke through but ignored Tomos Williams in support before Willis Halaholo's 33-year-old legs did not have the pace to finish Mason Grady's powerful break.

Halaholo was shown a debatable yellow card moments later for hands in a ruck and Toulouse made Cardiff pay.

Flanker Jelonch clinched the bonus point two minutes before half-time and Retiere sliced through for the fifth after Jacob Beetham's missed tackle.

Beetham had previously looked composed while Keiron Assiratti and Rhys Carre dominated the scrums.

Owen Lane made his first appearance since the opening game of the season and Alun Lawrence made his debut after returning from Jersey, but the difference between the replacement benches was stark.

Placines finished a line-out drive before Kinghorn crossed with the final play of the match.

Cardiff head coach Matt Sherratt said: "The players tried their hardest right to the end but the difference was every time Toulouse got a chance they took it because they've got a huge amount of power whereas we made a few mistakes and didn't have the same firepower in that area.

"For a lot of our young boys, that will be an experience that will accelerate their development as long as they sit down and learn from it.

"It's not just about experiencing it but also reflecting on what you can do better and what the best in the world did.

"We rested a few people and took a few off with one eye on the home games and Christmas derbies coming up because we have to be smart with how many minutes they all play given the size of the squad."

Toulouse: Blair Kinghorn; Matthis Lebel, Pierre-Louis Barassi, Pita Ahki, Arthur Retiere; Thomas Ramos, Antoine Dupont (capt); Cyril Baille, Peato Mauvaka, Dorian Aldegheri, Richie Arnold, Emmanuel Meafou, Thibaud Flament, Anthony Jelonch, Alexandre Roumat.

Replacements: Guillhaum Cramont, Rodrige Neti, Nepo Laulala, Piula Fa'asalele, Alban Placines, Paul Costes, Baptiste Germain, Santiago Chocobares

Cardiff: Jacob Beetham; Josh Adams, Willis Halaholo, Ben Thomas, Mason Grady; Tinus de Beer, Tomos Williams (capt); Rhys Carre, Efan Daniel, Keiron Assiratti, Rory Thornton, Teddy Williams, Shane Lewis-Hughes, Lucas de la Rua, Mackenzie Martin.

Replacements: Evan Lloyd, Corey Domachowski, Rhys Litterick, Josh Turnbull, Alun Lawrence, Ellis Bevan , Harri Millard, Owen Lane.

Sin Bin: Halaholo (38)

Referee: Anthony Woodthorpe (Eng)

Assistant referees: Hamish Grant & Jamie Leahy (Eng)

TMO: David Rose (Eng)