Thursday 1 October 2015 15:24, UK
Paul Merson says he does not understand Arsene Wenger's decision to leave Petr Cech on the bench for Arsenal's crucial Champions League clash with Olympiakos.
An error-strewn display against the Greek champions saw the Gunners slump to a second successive European defeat, following their Matchday One loss away to Dinamo Zagreb.
Wenger's decision to play David Ospina in goal instead of Cech proved to be costly as the Colombia international's bizarre error gifted the visitors their second goal in a 3-2 win.
And, speaking on Sky Sports News HQ, Merson criticised Wenger's team selection and claimed Arsenal's hopes of progressing out of Group F are now slim.
"It was a must-win game for Arsenal and they should have played their best team," he said. "Why English clubs don't play their best team beats me.
"If you look at Barcelona - who played Bayer Leverkusen - Messi was injured and they still played their strongest team.
"For Arsenal to make one signing for the whole year and not play him in the two biggest games of the season so far is beyond me.
"People say Arsenal have made it difficult for themselves but, for me, progression is now out of their hands.
"If Olympiakos or Dinamo Zagreb do the double over each other, then Arsenal are out - they are not going to beat Bayern Munich.
"Bayern Munich are the best team in the world at the moment, not Europe, the world. Arsenal have to completely rely on the results in the other two games.
"If either of those teams do the double, Arsenal will have to get nine points and I don't see them getting nine points."
Arsenal face a sterner test this weekend with Premier League leaders Manchester United heading to the Emirates on Super Sunday.
The Gunners head into the game looking to atone for Tuesday's poor showing, while victory for United, according to Merson, would cement the Reds' status as genuine title contenders.
"The Manchester United game is a must-win game and Arsenal have put themselves under severe pressure now," he added. "This game is a big as it gets, it's Super Sunday with a capital 'S'.
"There is not much that can be changed in terms of players, obviously the goalkeeper has to come back in. He is a world-class goalkeeper, you play your best players.
"I'm one of Manchester United's biggest critics, they haven't done well and they are not as good as they used to be.
"But if they win this game they will become massive players in the Premier League title race. If they can go to the Emirates and win then they will be big, big players."
Watch Arsenal v Manchester United live on Super Sunday, 3:30pm, Sky Sports 1 HD