The Welshmen, with eight points from their travels swept to a 3-1 lead before Bryan Robson's side mounted a comeback with a Chris Armstrong goal five minutes from time as skipper Chris Morgan snatched a point in injury time.
Cardiff had carved out the early chances Jimmy Floyd Hasselbaink trying his luck with a free-kick from 20 yards but the United wall held firm.
Defender Roger Johnson went close with a header as he connected with a Kevin McNaughton cross from the right flank before United snatched the lead in the 18th minute.
Alan Quinn saw his fierce strike from the edge of the box take a deflection as the ball flew over the top and Lee Hendrie delivered the perfect, corner bundled over the line from three yards by Beattie.
Cardiff were level 14 minutes later the goal started and finished by Joe Ledley. The midfielder fed Robbie Fowler, whose cross was missed by Hasselbaink and Paul Parry, the ball falling at Ledley's feet, who finished clinically with a low drive from 18 yards.
The Welsh side escaped on 35 minutes as David Carney, on for the injured Keith Gillespie pumped in a teasing corner, skipper Chris Morgan headed from close range as the ball was cleared off the line by Glenn Loovens.
Morgan was the villain in first-half injury-time as Cardiff went ahead, Ledley's corner was met by the big centre-back who slammed the ball clear as Johnson was sent tumbling in the box.
Ice cool Fowler stepped forward sending Paddy Kenny the wrong way as he tucked the ball into the right-hand corner.
Beattie saw a dipping shot from 16 yards tumble onto the roof of the net before Gavin Rae hit Cardiff's third in the 59th minute, tucking his low drive from a tight angle beyond Kenny.
However, Armstrong drilled in a 25-yard strike five minutes from time with Morgan heading in from close range in the dying seconds to complete the late drama.