Although not really tested by the pointless Iron, Gary Johnson`s men were more than impressive, with Keanu Marsh-Brown setting them on their way before the break.
Reuben Reid made it 2-0 not long after it, before substitute Gozie Ugwu scored a late brace.
Tranmere are second, despite surrendering their perfect record with a 1-1 draw at Shrewsbury.
It was a point they were grateful for, though, with Jean-Louis Akpa Akpro scoring with two minutes left after Marvin Morgan`s first-half opener.
Next are Swindon, who beat MK Dons 1-0 thanks to Matt Ritchie`s goal, while Stevenage are fourth after Lucas Akins` penalty earned them a 1-0 win at Oldham.
Former Iron defender Andy Butler's 80th-minute strike helped Walsall leave Notts County with a 1-0 win, while Doncaster also lost their perfect record as Nick Ajose scored the only goal for Crawley at the Keepmoat.
Bournemouth and Preston both remain without a win after a bad-tempered 1-1 draw at Dean Court.
Harry Arter was sent off for the home side inside 27 minutes, but Tommy Elphick still gave them the lead before Akpo Sodje equalised.
Portsmouth took on the longest journey in the division as they headed to Carlisle, and were sent back on their way with a 4-2 defeat to reflect on.
In a quite bizarre game, United were 2-0 up when the clock struck 90 through Jake Jervis and Danny Livesey.
Chaos then set in, with Ashley Harris making it 2-1, James Berrett 3-1, Conor Clifford 3-2 and Paddy Madden 4-2 in a dramatic ending.
Previously-winless Brentford cut loose against Crewe at Griffin Park, running up a 5-1 scoreline.
James Donaldson started and finished the scoring, with Farid El Alagui (two) and Harlee Dean netting in the meantime, while Mathias Pogba scored for Alex.
Colchester and Sheffield United drew 1-1, with the home side`s Clinton Morrison cancelling out John Cofie`s opener, while Coventry are three draws from as many matches after throwing away a two-goal lead against Bury.
Adam Barton and Carl Baker netted for the Sky Blues before the break, but David Healy`s second-half penalty and Lenell John-Lewis turned things around.
Leyton Orient and Hartlepool`s game at London Road was unable to kick-off as the away side were caught in heavy traffic.