Gary Phillips fired a last-minute winner to secure Albion Rovers' first major victory over Motherwell and send their Lanarkshire neighbours out of the William Hill Scottish Cup in a significant fourth-round shock.
Rovers restricted Motherwell to few chances, with goalkeeper Neil Parry only serious tested once when he saved John Sutton's late header.
And the team sitting third bottom of the Scottish Professional Football League stunned the side who are third top when Philips struck a first-time effort from 18 yards to seal a 1-0 win.
Inverness eventually eased themselves into Monday's draw despite a power cut threatening to cause the abandonment of their 4-0 fourth round victory at home to Morton.
A penalty by Nick Ross in the 45th minute had put Inverness 1-0 in front, before the lights went out during the interval due to a major substation that serves part of the city going down.
However, after a delay to the start of the second half of around 35 minutes, the game was played to a conclusion.
Billy McKay scoring in the 71st and 88th minutes, before Aaron Doran completed the scoring from the spot in injury time after Scott Taggart was shown a red card.
Goals from Stevie May and Sanel Jahic eased St Johnstone past Livingston with a 2-0 win at McDiarmid Park.
The Scotland Under-21 player opened the scoring in the 24th minute with his 12th goal of the season but two fine saves from Saints keeper Alan Mannus, both from Callum Fordyce headers, kept the game level at the interval.
The Northern Irishman had another save from Marc McNulty early in the second half before Bosnia and Herzegovina defender Jahic, making his first start since joining the Perth club last month after leaving Turkish club Karabukspor, grabbed a second in the 61st minute from almost on the line.
The Championship side, however, could perhaps count themselves unlucky at the end of a decent afternoon's entertainment.
Top-flight St Mirren twice let a lead slip against Championship opponents Queen of the South as they were forced to settle for a replay after drawing their clash at Palmerston 2-2.
The Buddies looked like they had settled into the fourth round clash the quicker after Conor Newton put them ahead nine minutes in - only for Iain Russell to equalise 10 minutes from half-time.
Steven Thompson then had the Premiership side ahead for a second time with his seventh of the season but they were denied safe passage to the next round when Michael Paton struck with 18 minutes left.
The draw was not the result Saints boss Danny Lennon had envisioned as he sent his side out to gain revenge for Queens' League Cup triumph at the same venue back in August.
Hibernain won their first competitive match against Ross County in seven attempts thanks to a Daniel Handling goal just after the half hour mark which secured a 1-0 victory.
Handling struck in the 31st minute when he tucked away a through ball from Hibs captain Liam Craig.
But the Edinburgh side had to play for the last 20 minutes with 10 men after Paul Cairney was sent off when he was shown a second yellow card.
Rangers scraped through to the fifth round after late goals from Nicky Law and David Templeton gave them a 2-0 win at Falkirk.
The tie looked like it was heading for a replay after Lee McCulloch failed to convert from the penalty spot and the Light Blues struggled to break down a Bairns side who played the last half hour with 10 men.
But Law grabbed the opener with a minute of the regulation 90 to go and Templeton doubled the advantage deep into injury time as Ally McCoist's men left it late to book their place in the next round.