A remarkable goal from Galeno in the dying moments secured Porto a 1-0 triumph over Arsenal in the first leg of their Champions League last-16 encounter on Wednesday.

Arsenal, making their return to the knockout phase of Europe’s premier club competition for the first time since 2017, struggled to carve out clear opportunities against a resolute Porto defence. Their efforts were ultimately thwarted by Galeno’s sensational strike in the 94th minute.

This defeat halted Arsenal’s eight-match unbeaten run against Portuguese opponents and set them with a formidable challenge to reverse the deficit in the return leg in London on March 12.

"We lacked threat and aggression, particularly in the final third," Arteta lamented to TNT Sports. "There are areas we need to enhance to mount better attacks. We're capable of doing better."

Facing an uphill battle against Porto, a team renowned for its defensive organization, Arteta acknowledged the challenge ahead. "They're exceptionally well-drilled defensively and consistently disrupt your rhythm," he noted.

The Gunners, who last reached the Champions League quarter-finals in 2010, now confront a daunting task against their Portuguese counterparts.

"When it's 0-0 and you're approaching the 93rd minute, if you can't secure the win, ensure you don't concede," commented Arsenal midfielder Declan Rice. "Conceding late is a real blow, but we know what needs to be done. We won't allow our spirits to wane."

Arteta opted for an unchanged Arsenal lineup for the third successive match, following their convincing 5-0 victory over Burnley at the weekend.

Porto's veteran defender Pepe set to turn 41 the following week and the oldest outfield player in Champions League history, marked his 119th appearance in the tournament. Arsenal's starting eleven boasted a collective total of 104 Champions League appearances before their clash at the Estadio do Dragao.

Despite their relative lack of Champions League pedigree, Arteta expressed confidence in his team's ability to contend with Europe's elite.

The Gunners had secured five consecutive victories in the Premier League, netting 21 goals in the process, as they chase their first league title since 2004. Their aspirations extend to clinching the Champions League trophy for the first time, with the final set to take place at Wembley.

However, Arsenal has never lifted the coveted trophy, suffering defeat in their lone final appearance against Barcelona in 2006. Porto, winners of the European Cup in 1987 and 2004, currently occupy third place in Portugal's top flight. Nonetheless, they provided a stern test for Arsenal.

While Arsenal dominated possession and dictated the tempo in the first half, it was Porto who came closest to scoring. Francisco Conceicao's delivery from the right found Galeno, who struck the post from close range before squandering a second opportunity. Arsenal, spearheaded by Leandro Trossard, Bukayo Saka, and Gabriel Martinelli, struggled to convert their set-piece opportunities, with William Saliba and Kai Havertz failing to capitalize on headers from corners.

Substitute Jorginho was introduced by Arteta in the final 15 minutes, but Arsenal's lack of a clinical finisher was evident as they fell victim to Galeno's extraordinary goal.