It was a romantic story, one to fire the dreams of a club and a town – just not the one that the neutrals had wanted. This FA Cup quarter-final was set up for Grimsby to make history, to become the first club from the fourth tier to reach the last four of the competition. Instead, it was Brighton that advanced – as was always going to be the case; 99 times out of 100, anyway – Roberto De Zerbi’s team penning the latest chapter of their fantastic season to ensure that the puns focused on seagulls feasting on fish. Grimsby, 15th in League Two, brought 5,000 fans and many more inflatable Harry Haddocks – their ubiquitous mascot. They had carried hope because their club had achieved something unique in the cup this season, knocking out five teams from higher divisions, most recently Southampton. It was a step too far, Brighton too strong as they advanced to only the third cup semi-final of their history. The strains of how they were “going to Wem-ber-ley” filled the air as the 18-year-old striker Evan Ferguson scored twice to supplement Deniz Undav’s early opener. Solly March and Kaoru Mitoma completed the rout and the truth was that the scoreline could have been heavier. Brighton have done so much this season, sitting seventh in the Premier League – on course for their best finish and points tally. They want European football for the first time and, also, a first major trophy. It is now about what they do next. Could they go one better than they did in the 1983 FA Cup final when they lost against Manchester United after a replay? For Grimsby and the supporters who made the 473-mile round trip to and from north-east Lincolnshire it was about creating memories, uniting as a community, the grandest of days out and, of course, brandishing those Harry Haddocks. They were first wafted en masse before kick-off as Sweet Caroline played over the PA system and the same scene would play out at full-time, even more boisterously as their players saluted them. The English? Eccentric? Nah … The Harry Haddocks go back to Grimsby’s fifth-round tie against Wimbledon in 1989 but the club’s history with the competition is deeper. Remarkably, they were chasing a third appearance in the semi-finals here, following those in 1936 and 1939. There were not too many people who gave them a prayer. Brighton are a much bigger fish than Southampton these days and, if their line-up was imposing, then so was their start, Undav scoring on six minutes after the goalkeeper, Maxime Crocombe, could only parry a Moisés Caicedo blast. Up in the stands, baseball cap pulled low, De Zerbi showed no emotion. He was serving his second touchline ban in as many weeks; the first had been in the 4-0 home win against West Ham. “Four-nil, five-nil … maybe I get a season ticket there,” De Zerbi said, with a smile. Grimsby’s journey to this point had been astonishing. Never mind the scalps they had taken on this dream cup run, they were not even a Football League club last season. They won promotion via the National League play-offs after a sixth-placed finish. Paul Hurst set up with five across the back and four in midfield. The Grimsby manager knew what the order of the day would be, especially with Pascal Gross stepping forward when Brighton had the ball (which was often) to become an auxiliary inside or outside right. After the early concession, it was a triumph for Grimsby to reach the interval at 1-0. They barely crossed halfway, the pulses of their supporters only quickened when Lewis Dunk nearly overcooked a long-range back pass with Robert Sánchez off his line. Sánchez also seemed to get away with a handball outside his area with Danilo Orsi in attendance. The VAR was unmoved. But if Brighton were off colour in the first-half, Hurst’s team were disciplined and did not give up many chances. That changed in the second period, Brighton adding a more clinical edge to their possession, Ferguson’s first goal extremely tidy. He pulled down a chipped pass from Alexis Mac Allister before taking another touch and finishing while his second was good, too, a run and cool shot following an Undav ball. He has seven goals for the season. “A special striker,” De Zerbi said. Brighton could have had more. Undav shot high after a March cross had deflected and hit the upright; Mitoma rolled past the far post; Ferguson was pulled back after an offside in the build-up; Adam Webster hit the post and Mitoma guided another clear chance wide. March’s goal was a fine header from Webster’s ball into the area while Mitoma, a menace with his quick feet and acceleration, would benefit from a big deflection. Grimsby merely wanted one moment in front of goal to go their way but it did not happen, despite the best efforts of the substitute, John McAtee. He was denied at close quarters by Sanchez and also saw the goalkeeper push away a curling shot from him late on.