National League side Barrow pulled off a major FA Cup second-round upset as they came from behind to win 2-1 at League One Bristol Rovers.
Byron Harrison netted twice to turn the tie around, cancelling out Rory Gaffney's 10th-minute opener before adding a second after 61 minutes.
Sixth-tier Curzon Ashton had looked set to cause a shock of their own but suffered heartbreak against AFC Wimbledon as they lost a 3-0 lead to go down 4-3 in a crazy match at Tameside Stadium.
Adam Morgan completed a hat trick in the 62nd minute to put the hosts in complete control, but their League One opponents levelled with goals from Tom Elliott, Dominic Poleon and substitute Tyrone Barnett in the 80th, 81st and 82nd minutes.
Elliott then headed in his second in stoppage time to send the Dons through.
League Two Cambridge recorded a comprehensive victory over opponents from the division above, thrashing Coventry City 4-0 at home, with Luke Berry scoring all the goals.
Midfielder Berry notched a first-half hat trick -- the middle effort being a penalty -- before adding his fourth towards the end.
Eastleigh, of the National League, secured a 3-3 draw at home to sixth-tier FC Halifax thanks to Mikael Mandron's 90th-minute leveller.
Mandron had opened the scoring before Jordan Sinnott, Scott Garner and Richard Peniket scored in quick succession after the break to put the Shaymen 3-1 up.
Scott Wilson pulled a goal back and Mandron then ensured both sides' names will be in the hat for Monday's third-round draw.
Another non-league side in the draw are seventh-tier Stourbridge, whose home tie against Northampton was postponed due to a frozen pitch.
Braintree battled bravely at League One Millwall before being beaten 5-2.
Michael Cheek gave the National League visitors an early lead, but Millwall replied swiftly through a Harry Smith double and Shane Ferguson's effort before Jack Midson made it 3-2 10 minutes before the break.
Smith tcompleted his hat trick soon after the interval, and Aiden O'Brien added another at the death.
Woking, another National League outfit, had Charlie Carter sent off as they lost 3-0 at home to Accrington.
Carter was dismissed shortly after Stanley went 1-0 up through Billy Kee, who struck again with half-time looming. John O'Sullivan added his name to the scoresheet in the second half.
Elsewhere, Notts County snatched a replay against Peterborough as they battled back to seal a 2-2 draw at home.
Posh appeared to be cruising after early goals from Leonardo Da Silva Lopes and Gwion Edwards, but Adam Campbell made it 2-1 and the visitors had Lee Angol sent off, with Louis Laing levelling the tie in stoppage time.
Bolton advanced with a 3-2 win over Sheffield United at the Macron Stadium, where Gary Madine and Sammy Ameobi put the home side in charge.
Paul Coutts responded for the Blades but Josh Vela then netted Wanderers' third, with Jack O'Connell's effort proving only a consolation.
The day's other second-round tie saw Port Vale thump Hartlepool 4-0 at home.
Vale were 3-0 ahead at half-time courtesy of efforts from Rigino Cicilia and Alex Jones either side of a Michael Woods own goal, and Ryan Taylor scored a penalty early in the second half.