Millwall's Under 23s suffered a 4-2 defeat to Watford in the Professional Development League at Clarence Park on Monday afternoon.
Jayden Davis and Abdul Abdulmalik found the net for Kevin Nugent's side, but both strikes were no more than consolation as a strong Hornets side scored four times to take all three points.
The Lions were without the injured Hayden Muller and the suspended George Alexander for the trip, and the first goal came in the 29th minute as Kane Crichlow took a long pass in his stride to beat Ryan Sandford.
That lead was to last just three minutes, however, as Davis equalised, but deep into first-half stoppage-time the hosts were back in front after Phoenix Patterson turned home Crichlow's cross.
Two defensive lapses at the beginning of the second-half ensured that the game was put beyond The Lions' reach. Firstly, Tiago Cukur was fouled in the box before stepping up to convert a penalty which saw Watford's lead extended to two, with Maurizio Pocehttino adding The Hornets' fourth.
Abdulmalik reduced the deficit to two just after the hour-mark, but no further goals were scored as The Lions slipped to defeat.
Next up for Millwall's Under 23s is a home game with Swansea City on Tuesday 2nd March.
Millwall: Sandford, Moss, Adom-Malaki, Duncan, Ransom, Strachan, Boateng, Skeffington, Abdulmalik (Penney 90+2'), O'Brien (Bate 85'), Davis (Allen 60'). Subs not used: Hammond, Miller.