Before ye go...there's more Scottish Cup action on BBC Two Scotland now, with the highlights from this weekend's fixtures.
It's been a long day of Scottish Cup action - and not one upset on the cards.
Celtic thump St Johnstone - again, while Aberdeen ease aside the challenge of Queen of the South and Hearts end the fairytale progress of junior side Auchinleck.
Three more Premiership side are into the hat for tomorrow's draw, which takes place after the Highland derby between Ross County and Inverness Caledonian Thistle.
Join us for more live action from Dingwall on BBC Radio Scotland, online - and television too (BBC Two Scotland).
Queen of the South manager Gary Naysmith tells BBC Scotland: "I think 4-1 is probably a bit harsh. Derek [McInnes] has made a real good substitution at half-time and brought on Niall McGinn. He's probably been man of the match for Aberdeen.
"You've got to look at where we could have done better and two or three of the goals are preventable. I'm led to believe it's not a penalty. I've not seen it, that's just people leaving me messages.
"We've got to take the positives. For 60 minutes, there was nothing between the teams. We scored a fantastic goal. The players kept going, they were credit to the club today. We didn't sit back."
Tommy Sloan was disappointed with the early goal his Auchinleck side lost but couldn't fault the effort the juniors put in.
"There are huge positives for us," the manager tells BBC Scotland. "Even in the first-half, when we're getting a bit of a doing, this is where you want to be, playing at this level, so in a way I was enjoying it even though it didn't look like it probably.
"I couldn't fault the effort, but I was disappointed with the manner of the first goal, the biggest boy heads it into the net.
"There was a bit of a gulf in class in the first-half, I thought the big striker, Ikpeazu, makes a big difference, he's a real handful.
"In the second-half, we certainly had a few opportunities to score - I heard the supporters singing in the second-half, chanting away, the players responded in the second-half, so that was great."Copyright: SNS
Aberdeen manager Derek McInnes tells BBC Scotland he is pleased with second-half substitute Niall McGinn.
"It's good that we've got players of Niall's quality," he says. "I did think about starting him to stretch them. Niall's had a huge impact on the game.
"We were much better in the second half. It wasn't perfect, but it would be wrong not to acknowledge Stephen Dobbie's strike. Other than that, we didn't do much wrong.
"Queen of the South were very good, very organised. People may have thought we would wipe the floor with them, but it's never like that."
Hearts manager Craig Levein was happy his side had completed the "mission" of reaching the quarter-finals but thinks they let their "standards drop" after the break.
He praised returning striker Uche Ikpeazu.
"Uche was desperate to score today and there were opportunities when he could have fed people in, but I understand that he has been out for a while and wants to get on the score sheet," he says. "He's a good player, he attracts opponents and gives space to other players.
"Delighted for young Aiden Keena, probably the pick of the goals. It was good for him to get on and score.
"All credit to Auchinleck as well - thought they were very well-organised and difficult to break down."Copyright: SNS
Aberdeen substitute Niall McGinn turned the game in his side's favour against Queens.
"The manager called me at half-time and just wanted a spark in the game," he tells BBC Radio Scotland.
"Obviously disappointed I wasn't playing, but thankfully I made an impact. I scored straight away and helped with the assists as well.
"Queens set themselves out well and were hard to break down. With Dobbie as the striker, we saw how dangerous they can be.
"They caused us some problems in the first half, but thankfully we've got through as these ties are never easy."Copyright: SNS
Hearts manager Craig Levein is delighted with his side's win but has revealed an injury blow for Michael Smith.
The Northern Irish defender went off injured with 12 minutes remaining against Auchinleck and Levein has revealed that it is a torn muscle that could keep the 30-year-old from between six to 12 weeks.
Depending on the results of a scan to come, Smith could be out for the rest of the season.Copyright: SNS
So the quarter-final line-up is taking shape. Only two more places up for grabs.
Aberdeen, Celtic and Hearts progress today to join Premiership rivals Hibernian in tomorrow's draw.
Championship sides Dundee United and Partick Thistle also secured their places yesterday.
Rangers and Kilmarnock face a replay at Ibrox, while Ross County host Inverness Caledonian Thistle in their Highland derby tomorrow evening.
Former Scotland defender on BBC Radio ScotlandQuote Message: You look at Cosgrove for the first-half of the season and think what did the manager see in him - then all of a sudden he can't stop scoring goals. Confident, taking penalties, it's quite incredible the turnaround for Cosgrove. That punt McInnes has taken has paid off
Niall McGinn for his opening goal and two assists or Sam Cosgrove for his latest double? Stephen Dobbie for his stunning equaliser?
Vote for your man of the match by following the link below.
Former Scotland defender on BBC Radio ScotlandQuote Message: Aberdeen are worthy winners, but Queens can be proud of what they put into it. Special goal from Dobbie as well, but Aberdeen were just too strong. McGinn turned the game for Derek McInnes
Aberdeen's greater quality shows after the break.
Although Stephen Dobbie's 38th goal in 32 games this season cancelled out Niall McGinn's opener, further goals from Andrew Considine and two from Sam Cosgrove make it a convincing win for the Premiership side.
But it was McGinn's introduction as a half-time substitute that turned the game - the Northern Ireland scoring the opener and setting up the next two for the home side.
Lewis Ferguson tries his luck again from range, but this time the midfielder's strike flies over the crossbar.
The stuffing has been well and truly taken out of the visitors now and Queens midfielder Michael Doyle is down with a bit of cramp.
Lewis Ferguson's shot from 25 yards bounces awkwardly in front of Alan Martin.
It comes off the chest of the Queens goalkeeper, but there are no Aberdeen players following up to take advantage.
Aberdeen are just running down the clock. Five minutes plus stoppage time is not enough for Queens to mount what would have to be a sensational comeback.
The crowd's gone quiet as this game is finished as a contest.
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A chance for Queens as Stephen Dobbie picks it up deep inside the Dons penalty area.
The veteran is unable to get a sight of goal himself so lays it into the path of Lyndon Dykes, but his fellow striker's shot is straight at goalkeeper Joe Lewis.
Former Scotland defender on BBC Radio ScotlandQuote Message: I don't know what happened to the goal machine on that occasion because it looked as though from two, possibly three yards out, that Cosgrove has got to finish that. He's under a little bit of pressure, but surely it's easier to find the net?
Sam Cosgrove is presented with a chance to complete his hat-trick as Gary Mackay-Steven's cross puts it on a plate for the big striker.
However, he somehow manages to clip his shot wide of the far post from four yards out.