Mikel Arteta's side arrived at the Jose Alvalade Stadium rocked by successive defeats against Manchester City in the League Cup final and Southampton in the FA Cup quarter-finals.

Once again, the Gunners were below their best but they emerged with the win thanks to Sporting's lack of cutting edge and Havertz's clinical finish in stoppage-time.

Arsenal will be firm favourites to advance to the semi-finals in the second leg in north London on April 15, but they will have to improve significantly to win the tournament for the first time.

Those agonising losses to City and second-tier Southampton marked the first time that Arsenal had been beaten in successive matches this term, with the embarrassing FA Cup defeat just the Gunners' fifth of the season.

The after-shocks were still being felt as Arsenal struggled to find any momentum in Lisbon, but not for the first time this season they found a way to win ugly.

Aiming to finally banish accusations that they are English football's nearly men by winning their first major trophy since the 2020 FA Cup, Arsenal have faced pointed questions about their perceived lack of mental strength.

Grinding out the win in Lisbon was a suitable riposte to the critics.

Insisting his players were "hungrier than ever", Arteta had urged Arsenal to use the "pain" of their recent defeats as motivation and they rose to the challenge.

Sitting nine points clear of second-placed Manchester City, the Premier League leaders are also on course for their first title in 22 years.

Playing in the last eight for the first time since 1983, Sporting's 17-game winning run at home made them dangerous opponents for Arsenal.

Injury-hit Arsenal were still without Jurrien Timber, Piero Hincapie, Eberechi Eze and Bukayo Saka, although Declan Rice returned after missing the Southampton game and England's recent friendlies.

David Raya was also back in goal for Arsenal after missing the previous two games and the Spaniard quickly made his presence felt.

Ousmane Diomande's deft pass split the Arsenal defence, sending Maxi Araujo clear for a fierce strike that Raya tipped onto the crossbar at full-stretch.

Raya was forced into action again to smother Geny Catamo's low drive from an acute angle inside the penalty area.

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Arsenal were on the rack but Noni Madueke nearly gave them the lead against the run of play with an in-swinging corner that cannoned off the bar.

Unable to establish any attacking rhythm in a cagey half, it took Arsenal 42 minutes to muster a shot on target.

Even then Martin Odegaard's blast from the edge of the area was straight at Sporting goalkeeper Rui Silva.

Arteta's frustration was palpable as he urged Madueke and Ben White to press harder when Sporting were in possession.

Arsenal were marginally improved after the break and Leandro Trossard dragged his shot wide from 18 yards before Odegaard almost caught out Silva with a free-kick immediately after half-time.

Martin Zubimendi thought he had given Arsenal the lead in the 63rd minute with a close-range finish, but the midfielder's goal was disallowed for offside against Viktor Gyokeres.

Odegaard and Trossard limped off to add to Arsenal's injury woes.

Sporting went close to snatching a late goal when Luis Suarez's cross reached Catamo for a flicked header that Raya pushed away.

But Arsenal grabbed the winner in stoppage-time via Arteta's substitutes.

Gabriel Martinelli played a superb pass over the Sporting defence and Havertz beat the offside trap to slot past Silva from 10 yards as Arteta punched the air in delight.