Marine stunned Colchester by knocking them out of the FA Cup 5-3 on penalties, while 2013 winners Wigan were beaten by National League North side Chorley on Sunday.
Marine, of Northern Premier League Division One North West, took a shock 21st-minute lead when Anthony Miley followed up to score from close range after Josh Hmami's free-kick had rattled a post.
Colchester equalised in the 64th minute when Harry Pell found the net after Noah Chilvers' long-range effort had only been parried by Marine keeper Bayleigh Passant and not cleared.
Passant denied Josh Bohui and Michael Folivi had an effort cleared off the line as it went to penalties and, after Bohui's effort went wide, Michael Howard converted to send Marine into ecstasy.
Substitute Sonny Carey's late winner sent National League side King's Lynn into the second round for the first time in their history as they recorded a 1-0 shock victory against League Two Port Vale.
The game looked to be heading for extra-time when teenager Carey pounced in the 82nd minute after latching on to a pass from Adam Marriott.
Another youngster, goalkeeper Archie Mair, had pulled off a number of stunning saves to deny Vale, who were left cursing their missed opportunities.
Adam Campbell scored twice as non-league Darlington caused a first-round upset by winning 2-1 at managerless Swindon.
Sixty-five places separated the sides before kick-off but Campbell's double put the team who are 15th in the National League North in the draw for the second round for the first time since 2007.
National League side Boreham Wood shocked League Two Southend, winning 4-3 on penalties after a 3-3 draw.
Boreham Wood seemed set for a comfortable victory when Jamal Fyfield headed them in front after just eight minutes. Luke Garrard's side doubled their lead in the 51st minute with Mark Ricketts firing home.
But the Shrimpers, who are bottom of League Two without a victory to their name, got back in the game in the 59th minute with Brandon Goodship scoring from a narrow angle. Substitute Terrell Egbri brought Southend back level three minutes later with a close-range finish.
The Wood regained the lead three minutes into extra-time with Kabongo Tshimanga scoring from the spot and Southend equalised seven minutes later with an excellent effort from James Olayinka.
But Boreham held on and secured victory on penalties despite seeing their first spot-kick, from Shaquile Coulthirst, saved by Mark Oxley. Southend substitute Matt Rush saw his effort kept out by Nathan Ashmore before skipper Jason Demetriou fired wide of the left post to see the non-league side progress.
Ruthless Bradford cruised into the second round of the FA Cup after thrashing non-league Tonbridge Angels 7-0.
Defender Anthony O'Connor gave the League Two a sixth-minute lead with a close-range header from Connor Wood's left-wing cross before Billy Clarke bent a superb free-kick from 25 yards over the defensive wall after he had been fouled. Clarke got his second just before the break when he headed another excellent cross by Wood past Jon Henly.
The visitors stretched their lead in the 55th minute when Clayton Donaldson swept home a low cross from Callum Cook. Cook hit the post before finding Austin Samuels, who is on loan from Wolves, and the substitute scored his first senior goal with a composed finish after 68 minutes.
Harry Pritchard made it 6-0 in the 84th minute after good work by Samuels before Wood got Bradford's seventh from close range in stoppage time.
Dominic Samuel inspired Gillingham to a memorable FA Cup comeback as the League One side came from 2-0 down to beat National League Woking 3-2 at Priestfield.
The semi-professional visitors took the lead midway through the first half when former Wycombe midfielder Max Kretzschmar spectacularly fired into the bottom corner from the edge of the box.
Sitting 44 places higher than the Surrey club in the league pyramid, Charlton loanee Josh Davison appeared to put the Cards on the verge of the second round for the fourth time in five years when he pounced on a loose ball to double their advantage early in the second half.
However, the deficit was halved just four minutes later as Samuel met Jordan Graham's cross to head past Ross before the Gills fortuitously equalised on 68 minutes - Declan Drysdale's header hitting the bar and deflecting off an unaware Samuel into the net.
Substitute Vadaine Oliver completed the quickfire turnaround 11 minutes from time as he met another Graham delivery to head past the helpless Ross, and only the woodwork denied Kyle Dempsey a fourth late on.
National League South side Concord Rangers agonisingly missed out on reaching the second round for the first time in their history after they were defeated by Stevenage on penalties following a thrilling 2-2 draw.
Exeter squeezed through to the second round of the FA Cup with a 2-1 victory but they were made to work hard for their win by AFC Fylde. Alfie May scored twice as Cheltenham overcame the spirited challenge of South Shields with a 3-1 win.
Dagenham and Redbridge knocked out Grimsby with a 3-1 victory as Stockport saw off the challenge of Rochdale with a 2-1 win. Bristol Rovers also won by the same scoreline against Walsall.
Lincoln were big winners against Forest Green, beating them 6-2, as were Doncaster, who beat FC United of Manchester 5-1. Richie Wellens needed extra time to nab his first win as Salford City manager, eventually winning 2-0 against Hartlepool after a 0-0 draw in normal time.
Portsmouth also won in extra time, beating Ipswich 3-2 at Portman Road, while Crewe were also 3-2 winners against Bolton. Shrewsbury beat Cambridge 2-0 while Plymouth beat in-form Charlton 1-0 at The Valley.
Newport were 2-1 winners away at Leyton Orient, as were Peterborough at Oxford United. Mansfield also won on their travels, beating Sunderland 1-0 at the Stadium of Light, while Hull won 2-0 at home to Fleetwood. Tranmere also won their fixture 2-1 against Accrington.
Academy product Gabby Rogers struck the winner in stoppage time of extra-time as Yeovil progressed with a 1-0 victory at 10-man Bromley.
Rogers volleyed in his first senior goal just when it seemed penalties would decide this crazy cup tie. Bromley were reduced to 10 men in the 68th minute as Harry Forster was shown a straight red card for a poor challenge on Luke Wilkinson.
National League North side Brackley Town needed penalties to see off a spirited Bishop's Stortford after the Isthmian League side fought back from 3-1 down to draw 3-3 in regular time.
Elliott Ronto's timely drive fired Canvey Island into the second round for the first time in 19 years in a 2-1 win at Banbury United. The winner came three minutes after the higher-ranked hosts, who had hit the woodwork twice late in the first half, had levelled the tie.
Connor Hall's extra-time winner sent National League North side Chorley into round two for only the third time as they came from 2-0 down to beat 2013 FA Cup winners Wigan 3-2 after extra time.
Goals from Joe Garner and Tom James had put the home side firmly in control, but Adam Long was shown a straight red card for bringing down Harry Cardwell when through on goal shortly before the interval.
Elliott Newby and Cardwell got the visitors back on level terms and Hall scored what proved to be the winner in the second minute of extra time.
Stephen Gleeson converted two penalties as National League side Solihull Moors won 3-2 at Scunthorpe.
Gleeson opened the scoring after just four minutes after Cameron Coxe had been brought down in the area before John McAtee equalised for the League Two side at Glanford Park.
Krystian Pearce headed the visitors back in front shortly after the interval and Gleeson's second penalty 10 minutes from time made it 3-1 before Kevin van Veen's goal set up a nervous finish, during which the home side's Tyler Cordner
was sent off.
Fellow National League side Barnet also pulled off a shock with victory over League One Burton. Wesley Fonguck scored the only goal of the game from 20 yards after 10 minutes and the hosts held on despite having Matt Preston dismissed at the start of the second half.
A hat-trick from Tom Nichols helped Crawley edge an amazing 11-goal thriller at Torquay and avoid another FA Cup first round upset.
Gary Johnson's National League team led 2-0 in the first half and 5-3 in extra-time - but bowed out 6-5 to their League Two opponents at Plainmoor.
First-half goals from Aaron Nemane and Ben Whitfield had the hosts in control, before Crawley lost goalkeeper Tom McGill to a serious injury in the second half.
Nichols started the comeback from the penalty spot before Max Watters equalised in the 14th minute of the injury time related to McGill's departure.
Josh Umerah then fired Torquay back in front but there was still time for Jordan Tunnicliffe to equalise and force extra time.
Gulls captain Asa Hall looked to have finally settled the tie with two penalties in the space of five minutes, only for Nichols to drag them back on level terms before then sending Ashley Nadesan clear to grab the winner with penalties looming.
Oldham maintained their record of not losing a first-round tie against a non-league team since 1972 with a hard-fought 3-2 victory at Hampton and Richmond.
Ben Garrity's early opener for the visitors was cancelled out by Sam Deadfield's penalty, but Bobby Grant restored Oldham's advantage and Danny Rowe made it 3-1 before Deadfield set up a tense finish with his second goal 16
minutes from time. The hosts had Tyrell Miller-Rodney sent off at the end.
Isthmian League side Cray Valley Paper Mills were unable to pull off a shock as they lost 1-0 at Havant & Waterlooville, where Bedsente Gomis scored the only goal after 18 minutes before Godfrey Poku's 62nd minute dismissal for the
And League Two Morecambe edged past a spirited Maldon & Tiptree side 82 places below them in the pyramid thanks to an Adam Phillips penalty just before half-time.
Carlisle produced an amazing comeback to get the better of non-league Hayes & Yeading, who looked on course for victory after Omar Rowe and Amos Nasha put the home side 2-0 up in extra time.
However, defender Jon Mellish scored twice in the last three minutes to force a penalty shoot-out and also scored from the spot to help his side win 4-3, with team-mate Gavin Reilly holding his nerve to score the decisive penalty in sudden
Scott Fraser scored the decisive spot-kick as the MK Dons beat Eastleigh 4-3 on penalties after 120 minutes of action ended goalless, while Gary Madine scored twice and Jerry Yates was also on target as Blackpool won 3-0 at Eastbourne Borough to make sure of their place in Monday's second round draw.
The full schedule for this season's FA Cup has been confirmed, with the final due to take place on Saturday May 15, 2021.
Replays have been scrapped - for this season only - to ease pressure on the football schedule.
November 28: Second round
January 9 2021: Third round
January 23 2021: Fourth round
February 10 2021: Fifth round
March 20 2021: Quarter-finals
April 17 2021: Semi-finals
May 15 2021: Final