Championship strugglers St Mirren dumped Dundee out of the Scottish Cup, while holders Hibernian smashed eight past Bonnyrigg Rose to ease into the fifth round.
It was a day to forget for the two Dundee teams in the competition as St Mirren, propping up the table in the second tier, put aside their woes and secured a stunning 2-0 win at Premiership side Dundee.
Veteran striker John Sutton fired in a first-half opener at Dens Park, with Jack Baird doubling the lead soon after the interval.
Dundee United suffered a 6-2 defeat to Ross County, helped by a fine double by Chris Routis.
There were few problems for holders Hibs at Tynecastle who were 3-0 up inside 13 minutes, although Bonnyrigg Rose showed great spirit with Dean Hoskins pulling one back from the penalty spot before the break.
James Keatings and Jason Cummings both scored doubles as the visitors piled on the pressure with five second-half goals in an 8-1 win.
There was late drama at Rugby Park when Rakish Bingham came off the bench to score a last-minute penalty to give Hamilton a 1-0 victory against Premiership rivals Kilmarnock.
Adam Rooney and Niall McGinn scored two goals each as Aberdeen easily overcame League One side Stranraer with in-form Jonny Hayes instrumental throughout.
Morton impressed with a 2-0 triumph over fellow Championship play-off contenders Falkirk at Cappielow, while Inverness Caledonian Thistle fought back to avoid a fourth-round shock at Elgin City.
Mark Nicolson's dazzling free-kick put the League Two part-timers in front, only for Larnell Cole to equalise and Lonsana Doumbouya, who went close with two headers, slotted in the winner on 66 minutes.
Veteran forward Miller hit a late double to give Rangers a dramatic 2-1 win over Motherwell in the early kick-off at Ibrox.
Chris Erskine scored twice in Partick Thistle's 4-0 win over Highland League club Formartine United, with Steven Lawless and Abdul Osman also on target.
Dunfermline were 3-2 winners at Alloa, but it was not as comfortable as it perhaps should have been after Nicky Clark, Paul McMullan and Joe Cardle had the visitors three goals up within the hour.
Nicki Paterson's 27th-minute goal was enough to edge East Fife to a 1-0 win at League One rivals Livingston.
Dylan Nguene Bikey's 84th-minute equaliser earned Stirling Albion a 2-2 draw and a replay against Clyde. Ayr United and Queen's Park will also have to face each other again after a goalless draw.
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