Second-half goals from Shaun Pearson and Patrick McLaughlin secured non-league Grimsby's progression into the third round of the FA Cup as they recorded a shock 2-0 victory over struggling Sky Bet League Two outfit Northampton.
Former Boston defender Pearson nodded home Scott Kerr's free-kick after 64 minutes before late substitute McLaughlin struck in added time to cap an impressive showing from the Skrill Premier hopefuls.
Callum Gittings and Michael Gash both struck twice as Kidderminster booked their place in round three with a 4-2 victory over League Two side Newport.
Harriers finished above County in the Conference last season but it was the Welsh side who earned promotion to the Football League through the play-offs.
However, it was Kidderminster's day in the cup as Gash and Gittings had the home side 4-0 up before Robbie Willmott struck twice in four minutes for the visitors late on.
Record signing Britt Assombalonga hit a hat-trick as Peterborough breezed through with an emphatic 5-0 success over fellow League One outfit Tranmere.
And it was also a great afternoon for Assombalonga's strike partner Shaun Jeffers, who celebrated a first Posh start with his first two goals for the club as Tranmere bowed out with a whimper as they failed to muster a single shot on target.
Goals from Francois Zoko, Lucas Akins, Luke Freeman and Filipe Morais brought an end to non-league Stourbridge's run as Stevenage won their second-round clash 4-0, while Skrill Premier side Macclesfield edged out Brackley 3-2 following a five-goal thriller at Moss Rose.
Jack Mackreth struck with nine minutes remaining to book Macclesfield's place in the third-round draw.
Danny Andrew and Scott Boden had the Silkmen two goals ahead inside 50 minutes and seemingly cruising through.
Brackley hit back, though, through Steve Diggin and Owen Story only for Mackreth to shatter the Skrill North side's cup dreams at the close.
League Two side Mansfield cast aside their poor league form to earn a 1-1 draw at Oldham and force a replay.
The Stags have suffered six consecutive defeats in League Two but top scorer Sam Clucas hit a fine equaliser at Boundary Park to cancel out Korey Smith's opener.
League Two Rochdale saw off League One high flyers Rotherham with a 2-1 victory.
Southend came from behind to advance when they beat fellow League Two high flyers Chesterfield 3-1 at the Proact Stadium.
Tendayi Darikwa gave the home side an early lead, but headers from Marc Laird and Anthony Straker put Southend ahead before former Chesterfield midfielder Kevan Hurst sealed victory late on.
Carlisle knocked out Brentford with a 3-2 win, Leyton Orient saw off Walsall 1-0, Dover's run ended following a 1-0 loss at MK Dons, Plymouth were 3-1 victors over Welling and Preston beat Wycombe 1-0.
Along with a draw for Oldham and Mansfield, Bristol Rovers and Crawley recorded a goalless stalemate, Fleetwood and Burton will play again following the 1-1 result and Hartlepool will travel to Coventry after they played out the same scoreline.