PORTO, Portugal: Arsenal manager Mikel Arteta bemoaned his team's lack of cutting edge as Galeno's sublime stoppage-time goal earned Porto a 1-0 win in the first leg of their Champions League last-16 tie on Wednesday (Thursday in Manila).
Appearing in a first knockout match in Europe's premier club competition for seven years, Arsenal struggled to break down an organized Porto defense before Galeno's stroke of brilliance in the 94th minute.
The defeat ended Arsenal's eight-game unbeaten run against Portuguese opposition and the Gunners with plenty of work to do in the return leg in London on March 12.
"We lacked threat. We lacked aggression, especially when we had the ball in the final third," Arteta told TNT Sports. "So we will tweak a few things to attack better. We can do better."
Arsenal last made it to the Champions League quarterfinals in 2010, when they beat Porto in the last 16, but it is the Portuguese club who now have the upper hand.
"I think it's a team that's very well-organized defensively and they break your rhythm all the time," said Arteta.
"We want to be in the quarterfinals, you have to beat your opponent and this is what we have to do at the Emirates."
Arsenal failed to register a single shot on target as their recent goal spree came to a shuddering halt.
"When it's 0-0, you look up at the clock and it's 93 minutes gone, if you aren't going to win the game then don't lose it," said Arsenal midfielder Declan Rice.
"It's a real kick in the teeth because we've conceded late but we know what to do. We're not going to let our heads drop."
Arteta stuck with the same starting lineup for the third game in succession following his team's 5-0 demolition of Burnley at the weekend.
Porto defender Pepe, who turns 41 next week and is the oldest outfield player in Champions League history, made his 119th appearance in the competition.
By comparison, Arsenal's starters had combined for a total of 104 before kickoff at the Estadio do Dragao.
While short on Champions League experience, Arteta has said his squad have the belief they can mix it with Europe's best.
The Gunners have started 2024 with five successive wins in the Premier League, scoring 21 goals in those games, and are firmly in the race for a first title in two decades.
As well as reigning supreme in England for the first time since 2004, the north Londoners are convinced they can also conquer Europe, spurred on further by the prospect of a Wembley final.
Arsenal have never won the Champions League — losing their only final appearance against Barcelona in 2006.
Porto, European champions in 1987 and 2004, are a disappointing third in Portugal this term, but frustrated Arsenal throughout.
They were happy to cede possession and allow Arsenal to dictate the tempo in the first half, but it was the hosts who created the best chance.
Francisco Conceicao darted in from the right and slid over a cross that looped off a sliding Gabriel, with Galeno rifling against the far post and then steering the rebound wide after the ball came right back to him.
William Saliba and Kai Havertz headed wide at corners either side of a Nico Gonzalez drive that sailed over in a physical opening 45 minutes.
Leandro Trossard, deployed again as the leader of the attack alongside Bukayo Saka and Gabriel Martinelli, lashed over on the volley from Rice's driven corner early in the second half.
Arteta made his lone change with a quarter of an hour left, replacing Trossard with Jorginho, but Arsenal's lack of a prolific striker was exposed and they were ultimately undone by a moment of magic from Galeno.