The Blues took the lead at the Emirates Stadium through Eden Hazard, but Antonio Rudiger's own goal and a victor from Granit Xhaka saw the Gunners progress to the final, in which they will face Manchester City.
However, this is where it gets a bit slapstick, his effort was deflected by Marcos Alonso's head onto Antonio Rudiger's head at just the right angle to take it past the bewildered Willy Cabellero in goal.
In part thanks to Wenger's shift to a three-man defense in the second half.
And fellow Arsenal star Jack Wilshere admitted that he feels the change in formation was needed, while praising the team spirit shown to grind out the win. We have to be up for it and ready to go.
This situation is also affecting strategy, because the Premier League outfit are reticent to offer long-term contracts to Conte's targets if they don't expect the manager to be around next season. That is not to say the Arsenal coach hasn't been to Wembley in this competition before, he has just fallen at the final hurdle.
For once, it's not the FA Cup providing cover for Wenger.
Monreal arrived at the Emirates as a relatively low-key signing from Malaga in 2013, but has since made almost 200 appearances for the club, and is one of Arsenal's most consistent performers.
David Ospina has urged Arsenal to move on from the loss of the "excellent" Alexis Sanchez after the victory over Chelsea in the Carabao Cup semi-final proved that there is life after the new Manchester United ace.