A late equaliser denied Arsenal victory in their Europa League clash against Vitoria Guimaraes in Portugal.
Shkodran Mustafi's second-half header looked enough for the Gunners to secure three points but the hosts scored in injury time to snatch a 1-1 draw.
Arsenal remain top of Group F, but will have to wait to secure their place in the next round of the competition.
Manchester United, Porto, Lazio, Roma, Celtic, Sevilla, Rangers and PSV are some of the teams that will be playing on Thursday.