Dundee United slumped to the joint heaviest European defeat by a Scottish side as AZ Alkmaar marched into the Europa Conference League play-offs.

Leading 1-0 from the first leg, the roof fell in as United conceded five goals in 23 minutes before the break.

Vangelis Pavlidis and Tijjani Reijnders both found the net twice and Hakon Evjen also scored before Dani de Wit and Mayckel Lahdo added to the misery.

It surpassed United’s heaviest European defeat – a 5-0 second-leg thumping by Dinamo Moscow the last time they qualified 10 years ago.

AZ move on to face Gil Vicente, the Portuguese having beaten Latvian visitors Riga, as Jack Ross’ side lick their wounds ahead of Sunday’s Scottish Premiership trip to face Heart of Midlothian.

United’s head coach had sacrificed the flair of first-leg scorer Glenn Middleton and handed a debut to Australia left-back as the experience of Charlie Mulgrew and Ian Harkes were brought back into the side after Sunday’s domestic defeat by Livingston.

The solidity shown in the first leg looked to have returned as they subdued AZ for the first quarter, but United failed to heed the warning signs as goalkeeper Mark Birighitti saved from Pavlidis and Evjen.

A flowing passing move opened up the United defence and Pavlidis tapped in his third goal of the season from a cut-back from Milos Kerkez.

United threatened to level, but goalkeeper Hobie Verhulst superbly palmed over Harkes’ athletic hitch-kick from six yards.

Visiting optimism began to dwindle as midfielder Reijnders fired low past Birighitti from 18 yards.

It disappeared completely after the United goalkeeper, moments after fumbling on the line under a Pavlidis challenge, punched thin air as he looked to meet an Evjen corner and the Greece striker headed into the empty net.

Reijnders fired home as United struggled to clear inside their penalty box before fellow midfielder Evjen rifled in a strike from 20 yards.

Any half-time advice imparted by Jack had little effect as AZ increased their lead in their first attack after the break as midfielder De Wit followed up from close range after a Pavlidis shot was blocked.

Substitute winger Lahdo drilled in the Dutch side’s final goal with 15 minutes remaining, but there was still time for Pavlidis to be denied a hat-trick – and United avoided going down in history with the worst-ever Scottish defeat – as his late drive struck the outside of a post.

Man of the match – Pavlidis (AZ)

What did we learn?

United received a major lesson – that they are obviously not as good as they thought they were after receiving plenty of plaudits from their impressive first-leg win over wily European operators.

They have endured a result not only embarrassing for a club that once famously reached the Uefa Cup final but for Scottish football as a whole.

Yes, AZ have now not lost in 20 European ties at home and United were always underdogs, even after establishing a 1-0 lead, but the way they capitulated will leave question marks over the mentality and ability of a group of players a number of whom have plenty of top-level experience.

AZ boss Pascal Jansen learned his lessons from the first leg to win the battle of strategies. Now it is up to Ross to find a way to somehow lift his players for their return, heads bowed, to the domestic scene.

What’s next?

United travel to face Hearts in the Premiership on Sunday (15:00 BST).