Mikel Arteta bemoaned a lack of aggression from his Arsenal side in the Champions League defeat at Porto but said it would be “cruel” to judge their return to the knockout stages on the last-gasp goal that settled the contest.The Gunners’ hopes of reaching the quarter-finals for the first time in 14 years suffered a blow as Galeno’s fine late strike saw Porto win 1-0 in the last 16 first-leg tie.Arsenal have the chance to turn the tie around in the return leg at the Emirates Stadium on Tuesday 12 March.