Declan Rice questioned the savviness of his Arsenal side for a lack of game management as they conceded a late goal to hand Porto victory with the match so close to finishing.
The first leg of the tie was goalless, and looking likely to stay that way, before Galeno struck a wonderful winner from just outside the box four minutes into stoppage time.
It gave the Portuguese side a slender advantage going into the second leg in London on March 12 - but Rice felt that Arsenal should have done more to ensure they got the draw, especially with the clock so late in the game.