Jamie McGrath’s double helped Aberdeen into the Scottish Gas Scottish Cup semi-finals and gave manager Neil Warnock a much-needed lift as the Dons beat Kilmarnock 3-1.

McGrath hit an early opener and rounded off the scoring during a comfortable second half for the home side at Pittodrie.

Graeme Shinnie had put the Dons two ahead and Kilmarnock could not make the most of the lifeline afforded by Danny Armstrong’s strike late in the first half.

Warnock had faced questions about his future ahead of the game after failing to net a win in his first six cinch Premiership matches. A run of 10 games without a league victory in total sees the Dons in third-bottom place and Killie have taken nine points off them this season.

But Aberdeen had not lost in 13 previous Scottish Cup meetings with Killie and the cups continue to be a bright spot in Aberdeen’s difficult league campaign, with the victory sealing a third trip to Hampden so far.

Aberdeen’s 11th-minute opener came as a result of a long ball from Stefan Gartenmann, which was just too high for Stuart Findlay to properly head clear.

Bojan Miovski’s backheel put Junior Hoilett in behind and McGrath was on hand to knock home the rebound after Will Dennis stopped the winger’s shot.

Kilmarnock responded well. The visitors claimed for handball in the box from Gartenmann but referee John Beaton and video assistant Andrew Dallas were both unconvinced.

Kyle Vassell volleyed over on the turn and both Liam Donnelly and Findlay failed to hit the target from free headers.

Aberdeen doubled their lead in the 33rd minute after Hoilett took a quick throw and crossed. Miovski laid the ball back for Shinnie, who had run off the back of Vassell, and the Dons captain sent a powerful strike into the roof of the net via a deflection off Donnelly.

Cheered on by a full away end in the 10,879 crowd, the visitors  got back into the game eight minutes later when Vassell got past Nicky Devlin and cut the ball back for Armstrong to sweep into the net first time.

Killie midfielder Liam Polworth hit a powerful shot straight at Kelle Roos before the break but the Ayrshire side could not maintain their pressure after the interval.

Aberdeen dealt well with some sporadic set-pieces and restored their two-goal lead in the 66th minute.

Left-back Jack MacKenzie overlapped and cut the ball back for McGrath to guide a shot home off the head of Findlay.

Kilmarnock manager Derek McInnes had replaced David Watson with Fraser Murray at half-time but he waited until the 76th minute before looking to change the second half from his bench. Former Aberdeen pair Greg Stewart and Gary Mackay-Steven came on along with James Balagizi.

There was no immediate transformation and Dennis saved well from Miovski before McInnes made his last roll of the dice, bringing on Innes Cameron ahead of Kevin van Veen.

But there was no way back for Killie and Warnock received a warm ovation as he celebrated with his players on the pitch.