Arsenal defender Laurent Koscielny has said that his side's new 3-4-3 formation has helped to restore their confidence following a poor spell of form.

The Gunners had lost seven of their previous 12 matches before manager Arsene Wenger opted to switch to a three-man defence for the first time in 20 years against Middlesbrough last weekend.

After overcoming Boro, Wenger stuck with the same system for Sunday's FA Cup semi-final against Manchester City, which they won in extra time courtesy of an Alexis Sanchez strike.

"There was a tactical turnaround but we have been working on it for 15 days," Koscielny told reporters.

"The system suits certain players but it's also good for the whole team. I think we have also found more confidence in this system with three defenders. We are more solid. Commitment and determination also helped us to win because over the whole game we played as a team and fought hard.

"Before this game we were in quite a dark period, we had lost confidence. This victory has allowed us to regain confidence and keep calm, even if not everything was perfect."

Arsenal have now won back-to-back matches for the first time since January.