Aberdeen 0-1 Motherwell
Motherwell leapt from fifth to second in the Premiership with a narrow win over Aberdeen.
Lionel Ainsworth scored the only goal on the counter-attack after a good run by Henri Anier.
The Dons best chance fell to Jonny Hayes who inexplicably sent a free header wide from just outside the six yard box.
And the visitors withstood a late bombardment to secure a third win on the bounce.
Despite losing the two previous meetings this season, Motherwell had not lost at Pittodrie since 2008.
Both teams had defensive problems to patch up for the match, with the hosts seeing Mark Reynolds joining Clark Robertson and Andrew Considine on the sidelines after the facial gash suffered against Caley Thistle.
Motherwell lost Stephen McManus to an ankle injury, with Fraser Kerr deputising for the former Celtic captain and Paul Lawson lining up against brother-in-law Russell Anderson for the visitors at the expense of the benched Iain Vigurs.
The Dons started the brighter, pinning Motherwell back with the best early chance being spurned by Hayes who replaced Reynolds in the starting 11 and at left-back.
Niall McGinn's tempting cross from the right found an unmarked Hayes who headed wide from eight yards in what was a glorious opportunity.
Motherwell striker John Sutton and Dons defender Joe Shaughnessy clashed heads and both had spells back in the dressing room.
On Sutton's return to the action he found himself goal-side of Anderson after riding a desperate lunge, but his tame effort was held by Jamie Langfield.
A McGinn free kick went just wide before Lawson's long-range effort went straight at Langfield.
Aberdeen pressed for an opener before the interval and almost found it when Willo Flood weighted a pass into the path of McGinn who went round goalkeeper Dan Twardzik but his effort at the angle was saved by the former Dons squad man.
Just as they had done in the Highlands on Saturday, the Dons conceded early in the second half.
Flood's header in midfield bounced off Ryan Jack and into the path of Anier who ran from his own half before putting it on a plate for Ainsworth, who side-footed past Langfield from six yards.
The game continued down its previous path as Aberdeen continued to take the game to their stuffy visitors.
Shaughnessy, Peter Pawlett and McGinn all went close for the Dons whose appeals for a penalty after Pawlett was upended in the box, were ignored by referee Kevin Clancy.
Anier was denied up the other end by a Shaughnessy block as Motherwell tried to hit on the counter as Pawlett blazed over Twardzik's bar.
McGinn had one last chance from a free-kick that flashed just wide in stoppage time.
But it was Motherwell who made it three wins out of three to move second and gain some revenge on the side that knocked them out of the League Cup.