Arsenal "collapsed" in a "nightmare" Champions League last-16 first-leg hammering at German champions Bayern Munich, says manager Arsene Wenger.
The Gunners were beaten 5-1 at the Allianz Arena, conceding four second-half goals after losing defender and captain Laurent Koscielny to injury.
The Premier League side will now almost certainly go out in the first knockout round for a seventh straight season.
"It's difficult to explain," Frenchman Wenger told BT Sport.
"Just before half-time we had two good chances to score. We came back and played well.
"In the second half we lost Koscielny very quickly - he came off at 1-1 - and finally we collapsed. Bayern are a better team than us as well.
"The third goal was a killer for our players because after that we had no response."
Arjen Robben fired Bayern into the lead, but Arsenal fought back and equalised when Alexis Sanchez followed up and finished his own saved penalty.
However, in the second half the Gunners capitulated, as Bayern excelled in a 10-minute period during which Robert Lewandowski restored Bayern's lead before Thiago Alcantara scored twice.
Substitute Thomas Muller scored late on to surely put the tie beyond the Gunners.
"The real problems were after the third goal," Wenger added.
"We lost our organisation and we looked mentally jaded and vulnerable from that moment onwards. The last 25 minutes was a nightmare for us."
Asked if Arsenal require "miracles" to now progress, the 67-year-old replied: "Of course."
The Frenchman fielded only three questions in his official post-match interview, which lasted less than three minutes.
'We played really well but it is not the final'
Bayern Munich boss Carlo Ancelotti has been under a little pressure despite his side sitting seven points clear at the top of the Bundesliga.
Wednesday's result saw them break a Champions League record as they sealed their 16th consecutive home win.
But the former Chelsea and Real Madrid boss refused to say the tie was over before the return leg at Emirates Stadium on 7 March.
"The performance was good," said the Italian, who has won the Champions League three times as a manager.
"We played really well, but it's not the final. We need to play the second game unfortunately.
"The result is really important, but we don't want to make a mistake. We have an advantage but we have to prepare for the next game in London.
"We want to play like we did tonight - same intensity, same spirit, same concentration. We want to avoid problems."