Against Vitoria de Guimaraes, Arsenal missed the chance to seal their place in the next round of the Europa League in mathematical form as Group F winners.
Unai Emery's side visited the weakest team, because the Portuguese were in last place and had not yet managed to score in their last three games.
The 'Gunners' drew 1-1 at the Dom Afonso Henriques stadium, but the coach of the London club seemed satisfied with the result: "They were the most difficult rivals that we have faced in the tournament."
"Portuguese football has good coaches and players, this is seen in the teams, they are doing a good job and they put us in difficulty," Emery said in a press conference.