Sports Mole rounds up Saturday's League One action as Walsall and Colchester United share the points in an eight-goal thriller.
Tony Humes's side looked to have won the game late on after Darren Ambrose put the home side 4-3 up with 10 minutes remaining but they will have to settle for a point after O'Connor found the net.
A win for Walsall would have put them top of League One but secure their place in second.
Aiden O'Brien scored a brace which sealed three away points for Millwall against Sheffield United at Bramall Lane.
Peterborough United cruised to a 4-0 victory over Doncaster Rovers, with goals coming from Gabriel Zakuani, Erhun Oztumer, Conor Washington and Callum Elder.
Goals from Abu Ogogo and Sullay Kaikai gave Shrewsbury Town a 2-0 victory over Bury, with the result condemning the visitors to back-to-back defeats.
Gillingham remain at the top of the League One table, as they scored a late equaliser to make it 1-1 against Southend United.
Nicky Ajose scored a last-minute equaliser for Swindon Town, after the home side had trailed 2-0 to Coventry City with five minutes of normal time left.
Tom Naylor and Abdenasser El Khayati scored late goals to give Burton Albion a 2-0 victory over Port Vale, after both sides had a man sent off.
Wigan Athletic move up to fifth in the table after their 1-1 draw with Bradford City.
Paddy Madden's brace gave Scunthorpe United a comfortable 3-0 win over 10-man Chesterfield, with Gary McSheffrey scoring the other goal for the visitors.
Jamie Proctor's first-half strike sealed all three points for Fleetwood Town away at Barnsley.
Blackpool continue to climb out of danger with a 2-0 victory over Crewe Alexandra.
Rochdale and Oldham Athletic share the spoils after playing out the day's only stalemate.
Results in full (half-time scores in brackets): Barnsley 0-1 Fleetwood Town (0-1), Blackpool 2-0 Crewe Alexandra (0-0), Bradford City 1-1 Wigan Athletic (0-0), Burton Albion 2-0 Port Vale (0-0), Chesterfield 0-3 Scunthorpe United (0-0), Colchester United 4-4 Walsall (0-2), Gillingham 1-1 Southend United (0-1), Peterborough United 4-0 Doncaster Rovers (2-0), Rochdale 0-0 Oldham Athletic (0-0), Sheffield United 1-2 Millwall (0-1), Shrewsbury Town 2-0 Bury (1-0), Swindon Town 2-2 Coventry City (0-0)