Paul Merson admits what the Arsenal icon saw from the Gunners at FC Porto ‘worries me’ after Mikel Arteta’s team lost 1-0 in the first leg of the Champions League last 16. A late goal by Galeno handed the Dragoes the aggregate advantage on Wednesday night as Porto made Arsenal rue Gabriel Martinelli cheaply losing possession. The Dragoes’ forward struck in the 94th minute after Otavio easily intercepted the Brazilian’s long switch of play. Galeno produced an exquisite finish to send his finessed shot out of David Raya’s reach. The Liga Portugal giants will now visit Emirates Stadium for the se…