Arsenal's back three is still a work in progress
The last time Arsene Wenger played with three at the back, I was in the team alongside Tony Adams and Steve Bould at Derby in May 1997.
If you want to play with a back three, you have to know the system inside out. It is not something you can simply adapt to overnight.
We first started playing this way under Bruce Rioch. Even though we had a group of experienced central defenders, the system was initially difficult to pick up. It required walkthroughs every Monday morning in training of scenarios we might face.
Arsenal reverted to a back three against Middlesbrough for the first time since May 1997
Derby County's last game at the Baseball Ground was the last time Arsenal played a back three
Martin Keown (right) challenges Robin van der Laan the last time Arsenal played a back three
Arsenal may have won on Monday night but they had a few teething problems — particularly when it came to Alvaro Negredo’s equaliser.
After Alexis Sanchez lost the ball high up the pitch, Stewart Downing bombed forward into the space vacated by Nacho Monreal at left wing back.
When Downing came in on his left foot, the central defenders should have held their line to catch the forwards offside.
Instead, they dropped deep too early and their marking was too loose.
Mesut Ozil rattled in Arsenal's second goal 12 yards out after Aaron Ramsey's knock-down
Alexis Sanchez gave Arsenal the lead with a sublime free-kick three minutes before the break
Alvaro Negredo celebrates scoring Boro's equaliser with team-mate Marten de Roon
Arsene Wenger admitted afterwards he played three at the back to negate the long balls
There were other issues. Aaron Ramsey and Granit Xhaka did not offer enough protection in front of the back three.
If Arsenal play this formation against stronger sides than Middlesbrough then their central midfielders must provide the defensive screen Nemanja Matic and N’Golo Kante give Chelsea.
If Ramsey wants to break forward then Sanchez or Mesut Ozil need to fill in for him. One player who benefited from the change of system was Alex Oxlade-Chamberlain.
While he could have done more defensively, Oxlade-Chamberlain was more effective going forwards. Playing at wing back forced him to be involved a lot more.
I can see Wenger persisting with the system between now and the end of the season. On Monday night, it was still very much a work in progress.
Arsenal fans travelled up North with banners calling for Wenger's dismissal despite the result