Roberto De Zerbi told Brighton supporters to get their passports ready but warned the club must continue improving ahead of their maiden European campaign next season. Evan Ferguson netted twice in the first half of Albion’s 3-1 victory over Southampton in front of a sold-out Amex Stadium, where Pascal Gross restored the two-goal advantage following Mohamed Elyounoussi’s header for the relegated Saints. The three points assured De Zerbi’s side would not finish lower than seventh, in the Europa Conference League spot, though a sixth-place finish and a Europa League berth are all but mathematically guaranteed. “Today is difficult for me because with my English I can’t explain my emotion,” said the Italian manger, who succeeded Graham Potter in September. “I think we deserve this. The club, the players, me, my staff, and the fans, they have to organise their passports to travel in Europe next year because we have to grow together.” De Zerbi, who last week was shortlisted for the Premier League’s manager of the season award, was increasingly animated on the touchline throughout Sunday’s contest, which was made more interesting when Elyounoussi nodded past Jason Steele after 58 minutes. It felt everyone in the stands held a single collective breath soon after when Theo Walcott lifted the ball over the Albion keeper but the potential Saints equaliser was chalked off for offside. Relief made way for elation when Gross fired in the hosts’ third from the edge of the area to put the game away. But De Zerbi warned booking tickets to Europe is just the beginning of a new era for Brighton, who now must ensure they have the squad to compete in four competitions next term. He said: “I think the history of the Premier League explains. It can happen, you achieve Europe and the next year you can find yourself at the bottom of the table. “Now is the crucial moment for the club. Not for Roberto, for the players, but for the club, because we have to keep this level. We have to build a squad to improve our level because I think (chairman) Tony (Bloom) and the club they don’t want to lose this level. “And to not lose this level we have to work harder in this transfer market, not only in the transfer market but to organise better and better and better because the victory can be dangerous. “If you celebrate the victory it’s right, it’s normal, but you have to improve. You have to work harder because you can lose the level.” De Zerbi admitted that at one point his high-flying Seagulls had set an internal goal of qualifying for the Champions League, adding: “I always think it is good for the players to fix the big target. “We have improved in mentality, we have improved in confidence, we had a target and we still have a target. We have to get another point to play in Europa League.” Anything below sixth for the Seagulls looks highly unlikely, with Albion enjoying a considerable advantage on goal difference and a game in hand on seventh-placed Villa, their final opponents of the campaign. Southampton were already relegated before Saturday’s contest. Ruben Selles’ contract is set to expire after the season, but he insisted that as far as he was aware reports about the potential appointment of Swansea boss Russell Martin as his successor were unsubstantiated. The Saints boss added: “About my future, again I’m not worried about my future. “I know that my contract expires at the end of the season and what the club decides, it’s going to be the club’s decision. “It’s not my decision, I cannot control it, so I cannot spend time on that.” Read More Charity boss speaks out over ‘traumatic’ encounter with royal aide Ukraine war’s heaviest fight rages in east - follow live Sam Allardyce has no regrets about taking Leeds job after damaging West Ham loss Lee Gregory’s face mask returned following Sheffield Wednesday appeal Ronan O’Gara reveals Ireland ambition after latest Champions Cup success