Per Mertesacker has revealed that he and his Arsenal teammates are "massively disappointed" with Thursday's 2-0 defeat to Southampton at St Mary's.
The Gunners missed the chance to leapfrog the Saints into fourth place in the Premier League table, as goals in both halves from Sadio Mane and Dusan Tadic did the damage.
Asked by Arsenal's official website about what went wrong, the German said: "A lot, when you see the result.
"We are massively disappointed because there was a good chance to really bounce back properly but they deserved to win because they did a bit more than us."
The frustration spread to the terraces, too, as an Arsenal fan was later arrested for evading stewards and confronting manager Arsene Wenger.
The North Londoners sit sixth in the standings, three points adrift of Ronald Koeman's side.
