Arsenal boss Mikel Arteta has reacted to the Gunners' shock 1-0 first-leg round of 16 defeat to Porto in the UEFA Champions League on Wednesday night.
The Gunners returned to Champions League knockout football for the first time since 2017, but failed to get anything from the game in Portugal in an encounter they were considered favourites for.
Heading into this first leg on form, the north Londoners had scored 21 goals in five Premier League matches, a run that included a 3-1 victory over Liverpool.
A stoppage-time winner from Porto winger Wenderson Galeno at the Estadio do Dragao means Arsenal will need to beat their opponents in the reverse fixture, set to be played on 12 March, by more than one goal.
Speaking after the game, Arteta bemoaned the lack of experience his players showed and conceded his side were short on aggression when it mattered.
"Obviously, we have to manage much better when you cannot win," he told TNT Sports.
"The way we handled the ball on three occasions in deep areas, it's not good enough. It's half-time, you want to be in the quarter-finals, you have to beat your opponent and that's what we have to do at the Emirates.
"We lacked threat, we lacked much more threat, more aggression when we had the ball in the final third, especially in the back as well, more purpose to hurt them.
"We can do better. We play at home now, we know them and we know what to expect."
Arsenal will go up against Newcastle United in the Premier League on Saturday, in what is a must-win match for Arteta's men, who are hoping to stay in the title race.