If there’s one thing that Tuchel’s switch to a 3-4-2-1 (or whatever you want to call it) has done, it’s given Chelsea the ability to dominate play on both flanks. With wingbacks, athletic wide centerbacks, and some extremely hard-working wide forwards, the Blues get much of their joy both with and without the ball when they’re out by the touchlines.
United, by comparison, don’t put the same emphasis on controlling the wide areas, given that their best players (i.e. Fernandes) are typically stationed more centrally. But, with weapons like Rashford, Dan James and Mason Greenwood, they can certainly be effective in those areas when need be.
Based purely on the formations they play in, Chelsea should have the advantage in the wide areas, if for no other reason than they’ll simply have more bodies there. The Blues will have more options to pass to, and more players to press the opposition in those areas. That being the case, if United can manage to establish any meaningful footing out wide, it could lead to Chelsea being ripped to shreds.
By virtue of the high possession numbers and the opposition they’ve faced, Tuchel’s side has relied on some extremely attacking wingbacks, both in positioning and personnel. The preferred pair, Marcos Alonso and Callum Hudson-Odoi, are effectively just extra wingers. Any defense they can contribute is just gravy. While that’s all well and good against Newcastle and Atletico Madrid, Manchester United have the tools to exploit those defensive liabilities with impunity should they be isolated against one of United’s pacier players. Give Rashford a few attempts to get in behind Alonso, and I promise you’ll see a goal or two for the Red Devils.
With that in mind, it’s absolutely crucial that Chelsea lock down the flanks. It’s the second most important thing the Blues can do defensively, right after shoving Fernandes deep in someone’s pocket for the full ninety minutes. The most reasonable solution is probably to go with a more conservative choice of wingbacks. I’d opt for Ben Chilwell and Reece James, personally. Both are more than capable of contributing to the attack while not being absolute sieves at the back. Given that Alonso and Hudson-Odoi both put in shifts against Atletico, a rest might be called for anyways.
If Chelsea can turn the wings into a no-fly zone for United, all of the attacks will be funneled towards the center, where there should be three able-bodied centerbacks standing in the way, and hopefully an N’golo Kante in there as well. That’s the easiest key to making sure Chelsea can dominate proceedings at their leisure with the minimum of danger.