Unai Emery is not a man for harking back to the past – and it is not as if he has much time to given the mounting issues of the present – but the prospect of a Europa League tie against Valencia summons one of his most intense football memories.

Five years ago, as manager of Sevilla, he came up against his former team Valencia in the semi-finals. With a 2-0 home advantage from the first leg, his team crumbled at the Mestalla and gave up three goals. It was stoppage time. His team were going out. Valencia’s fans were overjoyed. Then, with one of those startling stings in a sporting tail, Stéphane Mbia headed in the goal that flung everybody’s emotions upside down. Sevilla were suddenly through on away goals and Emery lost himself in overwrought celebrations, charging on to the pitch and enacting a classic from the José Mourinho playbook.

Valencia fans who had previously liked their old coach bemoaned a legacy tarnished. They have borne a grudge ever since. Sevilla went on to win the competition and bring Emery his first managerial honour – the first of three in a row that would bring him his reputation as Mr Europa League.

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While Emery himself has personal history with Valencia, Arsenal as a club bear long standing wounds from past experiences against this particular opponent. In 1980 Arsenal and Valencia contested a European final, the Cup Winners’ Cup, at Heysel Stadium in Brussels. At the end of a mammoth season, when Arsenal played 70 games with umpteen replays and adventures in all the cups, they ran out of ruthlessness at just the wrong time.

They lost two finals – the FA Cup by a single goal and then the Cup Winners’ Cup on penalties – within the space of five days. As Valencia took them into extra time and then the shootout, it was almost too much to bear. Their manager, the legendary Alfredo Di Stefano, described the penalties as “like giving birth”.

Valencia were a nemesis for Arsenal some years later when the two clubs were making new European waves striving to be contenders in the Champions League. They met twice at a time when they were both at a peak, and very closely matched. Both won their domestic leagues in 2002 and 2004, and they met in Europe the season before each title when they were in the ascendency, on the chase, feeling ambitious and close to achieving big things.

They represented something refreshing in the Champions League of the day, up and coming clubs outside of the usual suspects who already had titles behind them in Real Madrid, Bayern Munich, Ajax, Milan, Juventus. Valencia reached successive finals, in 2000 and 2001 (where they were vanquished by usual suspects). Still, their progressive team showed it was possible for clubs outside the historic elite to make inroads. Borussia Dortmund, winners in 1997, were cut from similar cloth.

Facebook Twitter Pinterest Unai Emery (left) won the Europa League three times in a row with Sevilla. Photograph: Aflo/REX Shutterstock/Aflo/Rex/Shutterstock

Although Arsenal would make their way to the final in 2006, and regret blowing it with their Invincible team in 2004 when they felt they had the talent to go all the way, the devastated demeanour of Arsène Wenger and his players when they met Valencia in 2001 emphasised another brilliant opportunity laid to waste. They were 15 minutes away from a semi-final against Leeds when John Carew, a 6ft 5in striker, headed Arsenal out on away goals.

Wenger was only five years into his reign at that point, still a fresh and energetic force, and he looked ghostly pale after that defeat. It was obvious he was crushed by the sense of a golden possibility squandered. Two of the team’s most coveted talents, Patrick Vieira and Thierry Henry, emerged from the dressing room and cursed a lack of ambition, wondering if Arsenal had the resources to go further in the competition. It felt revealing about the temperature of the club then that narrowly departing the last eight of the Champions League felt to their major protagonists like such a demoralising failure.

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The rendezvous between the clubs two years on had a similar ring to it. Close. Intense. Settled in the end at the Mestalla by that giant thorn in Arsenal’s side, Carew.

The current team are fresh from conceding nine goals in a week, via three damaging defeats, and Arsenal know they have to show a more competitive, and composed face against Valencia – reprising the kind of performance they showed in the last round against Napoli. Emery has called for renewed focus. “We are in the final sprint and we need to be fresh in our heads if we want to finish strongly this season,” he says.

The assessment of Emery and his impact on Arsenal took a hit with recent poor results against Crystal Palace, Wolves and Leicester that automatically puts more emphasis on the Europa League as a better bet for the route back in the Champions League Arsenal crave. A big lift is needed.