Leeds United under-23's fell to their first defeat in seven games in the Professional Development League as Millwall ran out 2-0 winners at The Den on Monday afternoon.
Carlos Corberan's side were much changed from the victory over Cardiff City last time out with up to ten players missing and even included trialist Dan Martin from Fulham in the starting XI for the trip to the capital.
16-year-old striker Ryan Edmondson, who has impressed for the under-18's of late, was also named on the bench after being called up to first-team training in recent weeks.
United started the better of the two sides with striker Sam Dalby, who has notched five times for the 23's since joining from Leyton Orient in January, latching onto a loose pass from the Millwall defence but the 18-year-old failed to make the Lions pay seeing his effort blocked.
It was the hosts who opened the scoring on the 19 minute mark as forward Isaac Olaofe pounced onto a ball over the top to slot home past the diving Kamil Miazek from close range.
United continued to push and good work from Bryce Hosannah almost levelled proceedings as he beat his man to work his way into the Millwall box and slide in a cross but the ball was eventually scrambled away after a moment of brief panic.
The Lions doubled their lead just before the break as captain Oriol Rey, who has started 27 out of 28 games for Corberan's side this season, was caught in possession. David Ajiboye burst through on goal and was brought down by a Romario Vieira challenge which Mason Saunders-Henry duly converted from the spot.
Leeds again pressed on in the second half but to no avail as Millwall stood firm with their two goal league intact. Alex Machuca went closest for the visitors as his thunderous strike sailed just over the bar before substitute Clarke Oduor hit the woodwork with a header.
It was as close as the Whites would come as they failed to scored in a league fixture for the first time since October and in doing so fell to their first defeat since January.
Millwall: Sandford, McNamara, Toffolo, Donovan, Debrah, Mbulu, Ajiboye, Wicks, Leighton, Olaofe, Saunders-Henry. Subs: Hanson, Wright, Mitchell, Tiensia, Diedrick-Roberts.
Scorer: Olaofe 19', Saunders-Henry 37'
Leeds United: Miazek, Hosannah, Martin, Rey, Casey, Vieira, Gomes, Shackleton, Dalby, Machuca, Balboa. Subs: Rea, Gotts, Siddiki, Oduor, Edmondson.
Referee: J. Packman