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 the MK Dons - who had Dean Lewington sent off - 1-0 thanks to Matt Ritchie's goal, while Stevenage are fourth after Lucas Akins' penalty earned them a 1-0 win at Oldham.
Andy Butler's 80th-minute strike helped Walsall leave Notts County - previously with a 100% record - 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.
Cash-strapped 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 quite exhilerating 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 three 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 got caught in heavy traffic.
England will debut their new away jersey against Brazil at the Maracana Stadium on Sunday. Get in the Gear
Germany is one of the top teams ever and they will play the US on Sunday.
Manchester City will try and win back the Premier League title with this new soccer jersey from Nike!
Jamaica is in need of a win against the U.S. Get the jersey of the Reggae Boyz.
Barcelona will wear this new home soccer jersey next season. They also have a new away jersey. Get them both.
The Nike Hypervenom is the latest cleat silo from Nike. It will change your game and is worn by the game's top players.
Support the USA national team with an official 2013 Centennial soccer jersey from Nike. Its Official.
The hoop soccer jersey is classic and cool. The USA hooped jersey is perfect for every fan. Get in the Gear.
Neymar's move from Santos to Barcelona is no doubt the biggest summer transfer.
The USA will wear their blue away jersey against Jamaica in their World Cup qualifier on Friday night.