Scottish Cup holders Dundee United will have to replay their fourth-round tie in Dingwall as they were held to a goalless draw at Tannadice by Ross County in a repeat of last year's final.
First Division Ross County had the ball in the net shortly after the break when Andy Barrowman poked home from five yards out but the referee ruled it out after he adjudged goalkeeper Dusan Pernis had been fouled by Scott Boyd in the build-up.
Scottish Premier League side United pressed forward for a winner with Scott Robertson and Morgaro Gomis both coming close as County goalkeeper Michael McGovern was the busiest man on the park, but the sides will met again at Victoria Park.
Aberdeen made easy work of Second Division opponents East Fife as a Chris Maguire first-half hat-trick helped them to a 6-0 win. The Dons striker notched a double and Scott Vernon got his ninth of the season before Maguire completed his hat-trick just before the break.
Vernon got his second of the match with just nine minutes remaining and Josh Magennis made it six in injury time as Aberdeen remain unbeaten under new manager Craig Brown.
SPL strugglers Hamilton put their league worries to one side as they ground out a 2-0 win over ten-men Alloa. On his return from injury Nigel Hasselbaink fired Hamilton into the lead after 33 minutes after their Second Division opponents had dominated early proceedings.
Hamilton were awarded a penalty in the 90th minute when Alloa goalkeeper Stephen Robertson brought down Jim McAlister. Robertson was sent off and was replaced by striker David Gormley in goal, who heroically saved Simon Mensing's spot-kick but there was still time for Flavio Paixao to head home an injury-time goal as Hamilton held on to win their first game at New Douglas Park this season.
Hibernian's poor form continued as they were held to a stalemate at Easter Road by Second Division side Ayr United. After a poor first-half Colin Calderwood's side improved after the break but failed to find the net as they continue their search for their first win in seven matches.
A late goal from Paul Tosh earned Montrose a replay against First Division leaders Dunfermline after a 2-2 draw at Links Park. Veteran Tosh slammed home an angled strike just before the half-hour mark to give the Third Division strugglers a lead they held on to until the 74th minute when substitute Pat Clarke bundled home an equaliser.
With just nine minutes remaining a shot cannoned off the post and rebounded off Andy Kirk into the net to put Dunfermline ahead but Tosh hauled his side level with his second of the match deep into stoppage time.
The Highland derby between Inverness Caledonian Thistle and Elgin City looked to be heading for a goalless draw until Dani Sanchez stuck a left-foot volley two minutes into stoppage time and Adam Rooney headed home his 12th goal of the season to give the top flight side a 2-0 win over their Third Division rivals.
St Mirren were held to a goalless draw at home by Second Division Peterhead. The Premier League side dominated but some resolute defending means Peterhead will welcome St Mirren to Balmoor Stadium a week on Tuesday for the replay.
Morton's match against Airdrie United, Falkirk against Partick Thistle, Queen of the South versus Brechin City and the third-round match between Threave Rovers and Stenhousemuir were postponed due to snow.
Premier League leaders Celtic are in action tomorrow against Third Division side Berwick Rangers at Shielfield while rivals Rangers are at home to fellow SPL side Kilmarnock on Monday night.