A dejected Arsene Wenger felt a more clinical Arsenal might have already booked a place in the Europa League final after a frustrating 1-1 semi-final first leg draw against Atletico Madrid.
The visitors were reduced to 10 men at Emirates Stadium as Sime Vrsaljko astonishingly collected two bookings inside the opening 10 minutes.
Alexandre Lacazette and Danny Welbeck both spurned chances to put Arsenal ahead before the break but the former made it seven goals in his past seven matches across all competitions with an expertly directed header from Jack Wilshere's 61st-minute cross.
However, Antoine Griezmann pounced on a slip from Laurent Koscielny to poach a vital away goal for Diego Simeone's side and end Wenger's final European home game at the helm on a sour note.
"Looking at the performance we had and the way the game went it was the worst possible result," he told BT Sport.
"We have to go there in a positive mood and qualify over there. We have to recover from a disappointment and prepare for the next one.
"It felt like an opportunity missed. We could already be qualified but it didn't happen. Their goalkeeper made many saves and you could see that they have the quality up front to take advantage
"We knew if we did not score the second one it was important we did not concede."
1 - Arsenal have lost just one of their eight semi-final first legs in European competition (W4 D3), while they’ve progressed from the tie on every previous occasion they’ve avoided a first leg defeat. Hope. pic.twitter.com/V95yHcKbHc— OptaJoe (@OptaJoe) April 26, 2018
Atleti's defensive obduracy was on full display as they battled with reduced numbers and LaLiga's second-placed team have not conceded in any of the past 11 matches at the Wanda Metropolitano.
Nevertheless, Wenger is refusing to be daunted by the task awaiting his team next week.
"You don't look at the statistics, you look at your performance and we know we can score anywhere," he added.
"First recover, because the players have given a lot, and then see what we can do over there.
"We have to go there with absolute belief to do it."
|Ponzio: River players will be ´idolised´ for Libertadores success|
|Champions League permutations: How Inter, PSG and Liverpool can progress|
|Kohli: India were better and deserved to win|
|Bears shut down Goff, Rams|
|India survive dramatic finish against Australia|
|Klopp calls for electric Anfield atmosphere against Napoli|
|Saints clinch back-to-back NFC South titles, Bears trump Rams|
|Bucks improve to 2-0 against Raptors with win in Toronto|
|Black Caps include Patel for Sri Lanka Tests|
|Maidana: River want Real Madrid clash|
|Cowboys top Eagles in OT behind stellar Cooper display|
|AC Milan evaluating Fabregas signing – Leonardo|
|WATCH: Steelers´ chance at game-tying field goal slips away|
|Hayne will plead not guilty to charges, says lawyer|
|Boca boss Schelotto: The only thing I feel is sadness|
|Cardinals´ Fitzgerald makes NFL history with most receptions for one team|
|River Plate´s Copa Libertadores star Gonzalo Martinez confirms January departure|
|Klopp: I was never worried about Salah´s form|
|Packers QB Rodgers sets NFL record for most passes without an interception|
|World Cup bulking hampered Man United form – Lukaku|
|Leonardo rules out Ibrahimovic Milan return|
|Warriors´ Green to return against Timberwolves|
|I feel for him… we´ll make it work – Butler responds to Embiid´s frustration|
|Torino draw no missed opportunity for misfiring AC Milan, claims Gattuso|
|We´ll always be linked together forever - Wade reflects on playing with James before final match-up|
|O´Sullivan wins record seventh UK title|
|Chiefs secure playoff berth, Saints win NFC South|
|River Plate 3 Boca Juniors 1 (aet, 5-3 agg): Quintero and Martinez clinch Libertadores title in extr|
|WATCH: Chiefs QB Mahomes throws no-look pass|
|Dolphins defeat Patriots on miraculous final play|
|Kizzire eagle snatches QBE Shootout victory|
|AC Milan 0 Torino 0: Donnarumma shines, Cutrone misses late chance|
|Back to the drawing board for West Indies - Chase|
|Copa Libertadores: Messi and Griezmann among stars in Madrid for River-Boca Superclasico|
|Brady sets NFL record for most career TD passes|
|Copa Libertadores: Tevez named on Boca bench for Superclasico final|
|Premier League needs VAR, right now! - Benitez fumes over Dean´s decisions|
|McCall expects Itoje to fit for the Six Nations|
|Solari salutes Real Madrid character after ´ugly´ Huesca win|
|Berbatov defends under-fire Lukaku|
|Sarries crush Blues to maintain unbeaten start|
|Newcastle United 1 Wolves 2: Doherty punishes Yedlin red with late winner|
|Deeney jokes he´ll ´smash´ former Watford star Richarlison|
|Huesca 0 Real Madrid 1: Bale ends drought as Solari´s men edge to victory|
|Ponting: Umpires not looking at no-balls|
|Bale ends longest LaLiga goal drought|
|Porter backs Brees for MVP, Saints for Super Bowl|
|Verstappen eyeing 2019 title fight|
|Wall ´shouldn´t have played´ against Cavaliers after scoring just one point|
|Hazard: Man City the best team in the Premier League despite Chelsea win|
|LeBron explains why he gave a Grizzlies employee his game-worn shoes|
|Bangladesh cruise to ODI victory as seamers punish Windies|
|Football will win over violence, claims CONMEBOL president|
|Alcorcon support Reus Deportiu over unpaid players|
|Saponara explains cheeky celebration after last-gasp leveller|
|Godin and Filipe Luis return to Atletico training|
|Kick It Out condemns alleged racist abuse of Sterling|
|Emotional Oosthuizen clinches South African Open title|
|The Sunday Seven - 7 Key Opta facts for NFL Week 14|
|Martino salutes Atlanta´s grand plan|
|India´s tail must show greater application - Bangar|
|Mourinho: Diogo Dalot can be new Gary Neville|
|Sterling hits out at media coverage of black players|
|Lyon roars with defiance as Australia aim for unlikely victory|
|Bulls coach Boylen: Hooked starters ´embarrassing´ in record loss|
|Martinez pays tribute to Martino, Almiron after MLS Cup glory|
|LeBron: Final Wade matchup will be bittersweet|
|Alvarez-Kovalev rematch set for February 2|
|Newcastle Jets 2 Brisbane Roar 0: Sheppard, Jair score first A-League goals|
|India close in on victory in first Test|