Manchester United's 3-2 victory over Roma highlighted a key tactical lesson for Michael Carrick. The introductions of Shea Lacey and Mason Mount stretched the pitch, solving central congestion and creating space for United to thrive.

Manchester United's 3-2 victory over Roma could offer head coach Michael Carrick an interesting tactical lesson. 

Sometimes, the solution isn't adding more players to the ​middle of the pitch, it is giving the players already there more space to operate.

Looking at United's average-position maps before and after the substitutions against Serie A teams, one thing stood out: width.

Before the changes, United appeared congested centrally, with several players occupying similar positions. 

United looked really congested in the middle. (Screenshot from Sofascore)

This can make attacking football difficult. Passing lanes become crowded, players have less room to turn, and opponents find it easier to defend narrow spaces.

Then came the introductions of Shea Lacey and Mason Mount.

Lacey, wearing No. 31, offered greater width on the left, while Mount (No. 7) helped stretch the right side. 

Their positioning gave United a different shape, with players occupying more space across the pitch rather than gathering around the middle.

There was also a defensive balance to the changes, with Nos. 4 (Matthijs de Ligt) and Nos. 6 (Lisandro Martinez) occupying deeper positions than Harry Maguire and Ayden Heaven.

United's average position after the subs.

The timing makes the tactical observation even more interesting. United scored two goals after Lacey came on, before Mount joined the action.

Of course, the average-position maps alone cannot prove that width was responsible for the improvement. 

However, they offer an interesting indication of how the team's structure changed.

This is something Carrick should seriously consider as United look to build on this rare victory.

Cunha appreciates Shea Lacey for setting him up for the winner.

United have attacking players capable of creating moments of brilliance, but they need the right conditions to do so. 

Having too many players operating in the same central spaces can limit their effectiveness.

Width is not just about getting to the byline and crossing. It stretches opposition defences, opens passing lanes and creates room for midfielders and attackers to operate.

Perhaps United don't always need more bodies in the middle, perhaps they need to make better use of the entire pitch.