Nigel Clough was encouraged by how his team adapted to playing with three central defenders in Sunday's FA Cup success at Cambridge United.
With Tony McMahon suspended and Aidy White ineligible, Clough opted to start with a back three of Harry Maguire, Neill Collins and Matt Hill, with Ryan Flynn and Simon Lappin as wing-backs and the Gaffer says the experiment was a productive one.
On the change in system, Clough explained: "We didn't have a recognised right-back, that prompted the switch to three at the back and Ryan (Flynn) was excellent as a makeshift wing-back. He relished the extra responsibility and made several timely tackles and blocks.
"With Tony suspended it seemed the obvious choice to go with three defenders and they were all comfortable with it, we worked hard on that shape during the week.
"It gives us something to revert to in the future when necessary. We need flexibility, although we do prefer to operate with a solid back four in place."
The Gaffer concluded by highlighting United's recent upturn: "We are continuing to improve, that is just two defeats in ten now, so we have to continue to build up that don't lose mentality because we are certainly making encouraging progress."