A second-half strike from striker Rhys Healey secured a second win on the bounce and a 1-0 win over Millwall for Kevin Cooper's Development side.
Healey's sixth goal in six games proved decisive, smashing home from close range just before the hour to break the deadlock, a lead which never looked in danger.
Torrential conditions at Cardiff City Stadium saw the early stages played at a slow tempo but it was a strong City DVP side, including Craig Noone, John Brayford, Joe Mason and Declan John who looked the more lively. Indeed it was Craig Noone who brought City's early effort, only to see it blocked at close range.
Declan John, enjoying his role on the left flank after making his senior debut for Wales last week, also came close as he hit his shot just over the bar. Noone once again looked to get involved shortly after only to be on the receiving end of a stern challenge from Will De Havilland.
It was a challenge that saw Noone depart just after the half hour mark, being replaced by Anthony Bell.
HALF TIME: Cardiff City DVP 0-0 Millwall U-21s
No changes for either side at the break, but it was Kevin Cooper's side who made the most of the early second-half running as Healey started to make a real impression on the match.
The former Connah's Quay man, made the most of the slightest of openings on the edge of the area only to hit his shot wide of the near post. Millwall responded, but wasted their opportunity to break the deadlock as Alfie Pavey fired over from close range.
Just two minutes later City were in front as Healey grabbed his sixth goal in six to fire the Bluebirds ahead from close range. After some neat play on the flank, Healey was at hand to smash home the rebound after an initial scramble on the line.
It was a goal that came on the hour, but proved decisive in this one as Millwall struggled to mount any serious challenge to City's lead in the closing stages.
It secured a second win on the bounce for Kevin Cooper's side.
FULL-TIME: Cardiff City DVP 1-0 Millwall U-21s
Cardiff City DVP: Moore, Brayford, Owen (Williams 81), Wharton, Amondarain, Oshilaja (C), Noone (Bell 36), O'Sullivan, Healey, Mason, John (James 88). Subs not used: Massaro, Hawkins.
Goal: Healey (58)
Millwall: Gerrer, Siafa, Bender, Powell, Nelson, De Havilland, McManus (Thompson 87), Onyedinma, Pavey (Philpot 67), Penny (Farrell 45), O'Brien. Subs not used: Webb, Beadle.