FC Porto stunned a drab Arsenal side with a wonderful last-minute winner from Galeno as the Portuguese side took a Champions League last-16 first-leg win to London.

After scoring 11 goals in their last two Premier League games, the Gunners had an off-night in Portugal and failed to register a shot on target for the first time in two years – and were left aghast as Galeno cut inside and hit a superb long-range effort past David Raya in the fourth minute of stoppage time.

Galeno should have put Porto ahead in the first half when he missed two sitters from close range – first hitting the post then somehow putting an even better chance from the rebound wide.

Arsenal’s best chances came from set pieces as William Saliba, Gabriel and Kai Havertz put efforts from dead ball situations wide. But Galeno’s dramatic winner means Mikel Arteta’s side will have to come from behind to progress to the quarter-finals when the second leg comes around on March 12.

“We lacked threat, we lacked much more threat. More aggression [was needed], especially when we had the ball in the final third, especially in the back with more purpose to help them,” Arteta said to TNT Sports after the game.

“We will tweak a few things to attack better especially because, to be fair, we haven’t conceded much at all. But we can do better.”

How Arsenal stumbled in Portugal

Arsenal’s young team looked nervous as the club took part in its first Champions League knock-out tie since 2017, looking jittery on the ball despite holding 70 per cent of the first-half possession

The best chance of the opening period – by an absolute country mile – fell to eventual matchwinner Galeno. Francisco Conceicao did brilliantly down the right and crossed for his fellow winger – who somehow struck the inside of the post from a few yards out.

The rebound fell back to Galeno and he put an even easier chance wide in what was a major let-off for Arsenal.

Porto had a couple more chances as Nico Gonzalez blasted over from distance before top scorer Evanilson fired straight at David Raya from inside the penalty area.

Arsenal’s best chances of the first half came from set pieces, with William Saliba and Kai Havertz – on two occasions – nodding good Bukayo Saka corner deliveries off-target. Saka also saw a cross deflected onto the top of the bar before half-time.

William Saliba had Arsenal's best chance of the night from a corner

The Gunners’ best opening after the break fell to Leandro Trossard, who blasted over after being found unmarked via Declan Rice’s corner, but the referee blew for a foul in the penalty area which may have ruled out any on-target shot.

For a long time, the only other opportunity of the second period saw Porto midfielder Pepe beat Havertz down the right and square to Evanilson – but Rice did brilliantly to deflect over the bar.

As the game ticked into stoppage time, Gabriel headed over a good chance from a free-kick, but Porto ultimately saved the best until last.

Rice’s pass was picked out by Wendell, who fed Galeno around 35 yards out from goal and his brilliant, bending long-range strike stunned the blunt Gunners.

Arteta: It’s half-time – we know about Porto now

Arsenal manager Mikel Arteta:

“We have to manage it much better. When you cannot win, the way we handled the ball on three occasions in deep areas is not good enough.

“But it’s half-time, if you want to get to the quarter-finals, you have to beat your opponent. And that’s what we have to do at the Emirates now.

“It is a team that is very well organised defensively. They break your rhythm all the time, there were like 35 or 37 fouls in the game.

“So allowing that as well is not good enough and there are certain things we have to do much better. We play them at home, we know them now, we know them. We know what to expect.

“We couldn’t even touch anybody, because everything was a free-kick. We will learn form that, prepare better and go and do it.”

Rice: We won’t let this get us down

Arsenal midfielder Declan Rice:

“When it’s 0-0 you look at the clock and it’s 93 minutes gone, if you can’t win the game, don’t lose it. Maybe we needed that savviness about us to stay in and get a draw in a tough stadium against a tough opponent. But there’s a lot to play for in the second leg back at home.

“It [the winner] was so frustrating, it was a whole mixture of play to be honest with you. There were a couple of giveaways on the edge of our box and we were breaking forward – and they caught us on the counter and he stuck one in the top corner, which for us is really disappointing.

“We just said in there, and we are so positive in there, that we had such a good start to 2024. We are not going to let this get us down. We have a big one on Saturday and then address this one in a few weeks’ time.

“They’ve lost just two games here all season – they know what they’re doing. You’ve seen Porto over the years in the Champions League – an honest, hard-working side with great players. They just made it really compact and difficult.

“We have to change our approach in the home leg and give it absolutely everything. This is the Champions League, this is what we want to be competing in, so even though we’re a goal down, it’s a nice goal to aim for where we can turn it around in the home leg.

“It’s just keeping our heads, it’s just hard to concede that late. We have the home leg in front of us, knowing we play at home with our fans and energy. You will see a team that plays on the front foot from the start, hopefully we can do that.”