The game kicked off in bright sunshine and the opening stages matched the weather with both sides getting the ball down and trying to play football.
This led to a number of early chances at either end with Pars keeper Dorus de Vries saving well at his right-hand post from Kevin McBride's right-foot drive.
At the other end the visitors responded with long-range efforts from Jim McIntyre and Adam Hammilll that flew over Graeme Smith's crossbar. The Well keeper was then delighted that McIntyre's next effort was hit straight at him.
After a Jamie Paterson effort had skimmed the bar on 24 minutes the Pars took control of the half, with some lively play in front of Smith's goal, but they had only a weak Scott Muirhead header to show for it.
Motherwell capitalised on Dunfermline's poor play at the start of the second half when they took the lead. Scott McDonald's run into the box was ended by a trip from behind by Phil McGuire.
The Aussie stepped up and coolly sent the keeper the wrong way with de Vries going right and the ball to his left.
Pars boss Stephen Kenny made a positive substitution brining on Mark Burchill for Muirhead on 62 minutes. However, within a minute McDonald popped again to double Well's lead.
This time he ran on to Paul Keegan's head flick before coolly picking his spot as he fired past de Vries. In the end Motherwell ran out comfortable winners.