Kai Havertz scored a stoppage-time winner as Arsenal beat Sporting CP 1-0 in their Champions League quarter-final first leg in Lisbon.
The second-half substitute slotted past Rui Silva late on to hand Arsenal a slim advantage ahead of the return leg at the Emirates Stadium.
Arsenal came into the match under pressure after suffering back-to-back defeats for the first time this season.
Sporting nearly took an early lead when Maxi Araujo struck the crossbar after a fine through pass from Ousmane Diomande.
The visitors dominated possession in the first half but struggled to create clear chances, with Noni Madueke hitting the crossbar directly from a corner.
Sporting remained dangerous on the counter and almost scored when Araujo set up Francisco Trincao, who fired wide.
Martin Zubimendi thought he had given Arsenal the lead, but his effort was ruled out after Viktor Gyokeres was adjudged offside.
The hosts pressed late on, but David Raya made key saves to keep Arsenal in the contest.
Havertz eventually sealed victory, giving Mikel Arteta’s side a crucial win and ending a two-game losing run.
The result boosts Arsenal’s confidence ahead of their Premier League clash with Bournemouth at the weekend.
Though not their best display, the win could prove decisive in Arsenal’s season as they chase major honours.
Arteta’s side struggled in attack despite controlling possession and lacking a forward in top form.
However, the gritty performance in Lisbon offers renewed belief heading into the decisive stage of the campaign.
The win also eases pressure ahead of their next league match after recent defeats to Manchester City and Southampton.
Arsenal were, however, dealt a setback as captain Martin Odegaard was forced off with an injury concern.
