Mikel Arteta claims Arsenal lacked "threat and aggression" as they slipped to a 1-0 defeat to Porto in the first leg of their Champions League last-16 tie.

Brazilian Galeno netted a curling effort in stoppage time to give the hosts the advantage going into the second leg at the Emirates on March 12.

It was an uninspiring display from the Gunners and Arteta, 41, did not hold back in his assessment of the performance.

He told TNT Sport: "We lacked threat. We lacked aggression, especially with the ball in the final third. We can do better.

"We have to manage much better. We cannot win with the way we handled the ball on three occasions in deep areas.

"If you want to be in the quarter-finals you have to beat your opponent and this is what we will have to do at the Emirates now."

Porto could have scored long before their late winner, with Galeno missing a wonderful chance in the 21st minute.

Arteta was complimentary of the Portuguese side, who defended well for long periods and stopped his Premier League title chasers from having a single shot on target.

The Spaniard added: "I think it's a team that's very well-organised defensively and they break your rhythm all the time.

"There are certain things we will have to do much better, we know what to expect."

Declan Rice, featuring in his first Champions League knockout game, explained how his side need more "savviness".

He said: "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.

"Maybe have the bit of savviness about us to stay in and get a draw in a tough stadium against a tough opponent. A lot to play for in the second leg."