The inquest into Arsenal’s Champions League humiliation in Milan was uncomfortable for Arsene Wenger and there will be more of the same if they exit the FA Cup at the hands of Sunderland today.Wenger’s side head to the Stadium of Light for the fifth-round tie knowing the competition now represents their last realistic chance of silverware this season.The manager made no attempt to disguise his shock and disappointment at his side’s performance in losing 4-0 to AC Milan and conceded that they have little chance of recovering the daunting deficit in the second leg.That increases the pressure on the meeting with Martin O’Neill’s team as the Gunners attempt to end their seven-year trophy drought.Criticism of Wenger has grown steadily over the course of the season, with some Arsenal supporters voicing their frustration at the manager’s apparent unwillingness to pursue higher profile – and more expensive –targets in the transfer market.Now the manager must attempt to revive his squad’s morale ahead of the Sunderland game if he is to avoid another crushing defeat.A miserable night for Arsenal was made worse by an injury to centre-back Laurent Koscielny, who was forced out of the game in the first half and joins Per Mertesacker on the sidelines.Mertesacker is out with an ankle injury and Wenger must decide whether to switch Alex Song to the back four or recall out-of-favour Sebastien Squillaci for the second meeting of these two teams inside a week.They met last weekend in the Premier League, when Thierry Henry’s late winner ensured Arsenal left the north-east with three points.Henry will not be returning to the Stadium of Light, however, as his loan spell from New York Red Bulls has now expired.