Southampton midfielder Jordy Clasie thinks he and defender Cuco Martina are to blame for the only goal in the 1-0 defeat at Sparta Prague.
Saints fell behind in only the 11th minute when Clasie and Martina failed to track Costa Nhamoinesu at Borek Dockal's free kick and the forward scored at goalkeeper Fraser Forster's near post.
The result means Southampton must win or draw 0-0 at home to Hapoel Be'er Sheva in December if they are to progress to the Europa League's knockout stages.
Southampton -- who have won only twice in their past eight games in all competitions -- again rarely looked like scoring, and discussing Costa's finish on the club's official website, Clasie said: "In the first half they won a free-kick from 20 metres, 30 yards and there is a miscommunication between me and Cuco and from there they score.