It was hardly the most enthralling of football matches but Stephen Robinson and his players won't worry about that after gaining some sort of payback for a 3-0 thumping when the teams last met in October.
Aberdeen played some of their best football that afternoon but this latest display shows why they are so desperate to get Matty Kennedy in from St Johnstone as they lacked real threat from anything other than free kicks or corners.
This result also means the Dons have amassed their lowest points tally after 22 league fixtures in any of the seven seasons they have started under manager Derek McInnes and the frustration was evident in the stands.
Not that this result should be viewed as much of a surprise as a look at the table will tell you Motherwell have the best away record in the division outwith the Old Firm but remain more vulnerable at home, something Hibernian will test on Saturday.
Talking of the Easter Road side, night games at Pittodrie won't just be for midweeks if Dave Cormack gets his way as Aberdeen's chairman is already trying to switch the Saturday fixture at home to Hibernian at the start of March to an evening kick-off.
It's the latest initiative from the Atalanta based business man to shake things up since replacing Stewart Milne in the role after the success last weekend of giving the Merkland Road Stand over to the supporters determined to create a more intimidating atmosphere.
The reason for wanting to make the move permanent was given more credence when the area reverted to hosting the family section last night when it was only a third full despite the importance of the game.
Not that there was a great deal for anyone to get overly excited early on as the teams vying to be best of the rest in the Premiership this season seemed more intimidated than inspired by the prospect.
Aberdeen, as has been the case too often lately, mainly looked a threat from set piece situations, explaining why they are thought to be ready to make an increased offer to get Matty Kennedy in from St Johnstone this month.
Niall McGinn did his best to give the home side the sort of quality delivery needed to turn their superior possession into a tangible lead but Ash Taylor steered one header wide while Sam Cosgrove was well policed for most of the opening period.
The one time he did get to Shay Logan's cross the ball broke to Andrew Considine but the veteran left back's shot was kept out by the feet of Mark Gillespie on one of the few times in the opening period the Motherwell goalkeeper was left exposed.
The visitors spent less time in opposition territory but they did create a few moments of anxiety, especially after 20 minutes when Mark O'Hara's cross picked out Chris Long in the penalty area.
Joe Lewis could only take the sting out of the striker's angled shot and was relieved to see Logan avert the danger completely by hacking the ball off the line, but that was as good as it got for Long.
Booked for encroaching and injured a couple of times, the forward who scored all three goals in their Scottish Cup win against Dundee finally gave way for Christian Illic after coming off second best in a hard but fair challenge with Dylan McGeouch.
That was with an hour still to go and initially it took the edge of even the limited attacking Motherwell managed but they adjusted sufficiently to take the lead with Donnelly showing both sides of his game.
First the most booked player in the Premiership this season picked up his 10th yellow card so far for a late tackle on Lewis Ferguson before breaking the deadlock in first half stoppage time.
This time Ferguson gave away a free kick, Liam Polworth floated a cross to the back post which should have been dealt with but somehow Donnelly found himself all alone to squeeze a header between Lewis and the upright.
The second half followed much the same pattern with Aberdeen seeing plenty of the ball but only really looking dangerous from set piece situations which the visitors just about coped with at times.
Cosgrove and Considine did have half chances from more excellent McGinn delivery but they failed to test Gillespie, the former heading straight at the goalkeeper while the latter hooked a shot over the crossbar.
Considine should have earned a penalty when for about the only time all night the visitors defence switched off at a free kick and Declan Gallagher seemed to wipe out the defender in the box but Willie Collum waved away strong complaints.
Not that McInnes could be faulted for ambition when trying to salvage the situation as attacking trio Ryan Hedges, Bruce Anderson, and even former Motherwell favourite Curtis Main were thrown on but all to no avail.