Martin Keown has claimed that Arsenal should have retained the services of goalkeeper Emiliano Martinez.
At a time when Bernd Leno was sidelined with a knee injury, Martinez made a positive impression between the sticks, helping the Gunners win the FA Cup.
While the North London outfit put the funds towards making several high-profile additions, Keown has cast doubt over the decision after Leno struggled against Rapid Vienna on Thursday evening.
Speaking to BT Sport, Keown said: "Having let Martinez go, who was magnificent, to see Leno making these types of mistakes, you wonder whether it was the right call.
"It was a difficult night for Leno. The team had their backs to the wall but showed very good character to get back into it.
"A couple of changes were made. I thought when they changed it actually and went to a back five, the pictures then became more familiar to the players and they found a way to win this match."
Martinez has started in each of Villa's four successive wins in the Premier League this season.