An outstanding defensive performance and a last-minute goal by Brazilian Wanderson Galeno brought down Mikel Arteta's Arsenal, who fell 1-0 to a Porto side that masterfully halted the London powerhouse.

The late goal in the first leg of the Champions League round of 16 was a well-deserved reward for Porto's defense, which thwarted one of Europe's best attacks, and a deserved punishment for a Gunners side that looked unrecognizable.

Seven shots, none on target, and 10 corner kicks, many of which resulted in offensive fouls, are some of the statistics for Arteta's side, which will need significant improvement not only for the return leg but also for the upcoming clash against Newcastle.

The typhoon that wreaked havoc in the Premier League appeared subdued at Do Dragão, with the hosts, led by Galeno, the hero of the match, creating the first and practically only dangerous chance in the first half.

The Brazilian struck a powerful shot off the post and then, with Raya completely beaten, failed on the rebound, a surprising error that even fooled the stadium's sound technicians, who began playing the music typically heard on Porto's goals.

Arsenal sought to impose its game, but its vast possession did not trouble the 'Dragons' defense, led by the experienced former Madridista Pepe, who stopped the rapid progression of Martinelli and Saka on the wings.

And when Pepe was beaten, Argentine Alan Varela stepped up, increasingly influential in all aspects of Porto's tactics and a headache for the Gunners' attack.

William Saliba was Arsenal's most active player and stopped most of the attacks from Porto's most dangerous players, Evanilson and Galeno, except for the goal that was to come.

As the match neared its end, coach Sérgio Conceição turned to Spaniards Iván Jaime and Toni Martínez to inject more dynamism and secure a lead at the Emirates Stadium, something they ultimately achieved.

As the four minutes of added time approached their end, a missile from Galeno outside the box found the back of the net past Raya, and the Estádio do Dragão erupted in jubilation.

Everything will be decided on March 12 in North London.