Arthur Gnahoua hit a second-half double to take Grimsby Town through after a scare against Slough Town in their FA Cup first-round replay at Blundell Park.
Rekeil Pyke and Danny Rose put the Mariners 2-0 up, only for the National League South side to fight back.
Goals from Slough's Tyrese Dyce and David Ogbonna levelled the tie before Pyke restored his side's advantage.
Gnahoua's brace sandwiched substitute Alex Hunt's effort before Jamie Andrews hit a late seventh as the League Two club sealed a second-round trip to Oxford United.
Slough were unlucky to fall behind when Gnahoua's effort deflected into the path of Pyke, who drilled it across goalkeeper Rohan Luthra into the corner.
Having also lost defender Temi Eweka to injury, the Rebels then suffered a further blow when Rose made it 2-0, sliding in to meet Niall Maher's flick-on at the far post.
But the visitors halved the deficit when the unmarked Dyce rose to head in from a corner kick - and Ogbonna brought them level, pouncing as Johnny Goddard's cross evaded the Grimsby defence.
Goddard's deflected attempt might even have earned Slough the lead, yet it was the home side who edged in front again on the stroke of half-time when Maher glanced on another corner and Pyke bundled in his second.
However, Slough dominated at the start of the second half and it needed Rose's header off the line to deny Goddard the equaliser.
But Pyke set up Gnahoua to give the home side some breathing space and, with Slough tiring, they added three further goals in the final quarter of an hour.
Gnahoua teed up Hunt to fire past Luthra and then found the net for the second time before Hunt's cross was nodded in by Jamie Andrews for number seven.
Grimsby Town joint-caretaker manager Shaun Pearson said:
"That was probably the least one-sided 7-2 ever. It was a really tough challenge, but we knew it would be going into the game anyway because Slough have been on a good run of scoring goals.
"We know from last season from being on the underdog side of these types of games that it's not always easy as the bigger team to go out and win, but we're pleased to win in the end.
"We're pleased with a lot of things - the fact we've scored seven goals is obviously the big positive and some of our attacking play was brilliant.
"We didn't have control of the game at the start of the second half but we put bodies on the line and that's what you have to do sometimes."
Slough player-manager Scott Davies:
"I'm extremely proud of how far we've come - Hayes and Yeading, Salisbury, Ebbsfleet and then taking Grimsby to a replay.
"For 60 minutes I didn't think there was much in the game, but the manner of the defeat in the end looks bad.
"I don't think the final score represents the performance. I think, for the first 20 minutes of the second half, we were absolutely brilliant and I thought the goal was going to come and when we didn't get it, it is obviously a big disappointment.
"I'm immensely proud of the lads still but I was disappointed in the manner of some of the goals we conceded because I think there were a few of us that gave up.
"There was emotion in the end in knowing the cup run was over and that bled in towards the end of the game."