Hearts 1-0 Aberdeen
Callum Paterson's early header gave Hearts their first William Hill Scottish Cup goal since 2012 and a fourth-round victory over Aberdeen.
Hearts completely dominated the first half at Tynecastle and were good value for their 1-0 win but Andrew Considine squandered a glorious chance to level midway through the second period and the visitors pressed hard in a thrilling finale.
Aberdeen's Ladbrokes Premiership title hopes also took a blow when Willo Flood followed fellow central midfielder Ryan Jack in suffering a hamstring injury.
There were a little more than two minutes gone when Hearts capitalised on the first of their nine first-half corners.
Alim Ozturk headed Sam Nicholson's deep left wing delivery towards goal and Paterson nodded into the top corner from close range.
It was his team's first goal in the competition since their 5-1 final thrashing of Hibernian and they looked determined to ensure the next followed quickly, giving Aberdeen a torrid time.
The visitors were all over the place. Osman Sow was causing numerous problems and Mark Reynolds was booked for hauling the Swede down after being turned 30 yards out.
The defending got more desperate and Kenny McLean sent an attempted clearance back inside his own box to give Hearts another chance before goalkeeper Danny Ward let slip of the ball, but Blazej Augustyn could only hit the side netting.
Aberdeen switched to five at the back and settled down but Hearts were looking solid and Nicholson had a shot saved on the break before the hosts launched another series of corners, one of which saw McLean clear Augustyn's header off the line.
Things got even worse for the Dons seconds later when Flood hobbled off. Peter Pawlett came on and Graeme Shinnie moved back into central midfield as Derek McInnes reverted to a 4-2-3-1.
Aberdeen striker Adam Rooney showed his frustration with a blatant push and both he and Igor Rossi were booked. Tempers remained frayed after the break and McInnes reacted angrily to counterpart Robbie Neilson's calls for referee John Beaton to take further action after a Shinnie foul.
Ozturk had a free-kick saved before the Hearts skipper escaped a penalty claim when Rooney and 3,500 visiting fans behind the goal claimed he had pulled the Irishman.
Aberdeen started to exert pressure and both McLean and Rooney failed to make the most of half-chances before the unmarked Considine missed the target from six yards after Jonny Hayes' shot fell into his path.
Sow came close on the break three times as Aberdeen left themselves more exposed but Hearts came under intense late pressure and Alexander made good stops from Niall McGinn and Ash Taylor