Chelsea weathered a storm, sometimes figuratively and literally, to leave the first leg of the Champions League semifinal with an away goal advantage. The Blues had control of the match for the majority of the time, but there were certainly periods where they melted a bit. Chelsea survived however, in part due to the grit they have been developing and in part because of Thomas Tuchel’s tactical tweaks.
Tuchel himself admitted he had planned on Real Madrid using a 4-3-3, even with Zinedine Zidane’s recent discovery of other formations. When Zidane ran out with three at the back to stall Chelsea’s three at the back, Tuchel had to adapt.
The main adaptation seems to have been Mason Mount in midfield, making more of a 3-5-2/5-3-2 shape off the ball in various phases. That left two up top to press while the midfield became smothered. This was not absolute, however, as Mount especially would be allowed to come out and press to assist Cesar Azpilicueta on the flank.
Occasionally, Real Madrid would change their build up from a 3-4-3 to a diamond in midfield. When this happened, Azpilicueta would slide over as Mount would shift forward. The Real Madrid midfield was then man marked, forcing them to beat players 1v1 in the center or go wide. With Azpilicueta tucking in, the right flank was left open but that proved to be a pressing trap that would force Real Madrid back or out.
Offensively, this change in shape also gave Chelsea some interesting options. With two up top, Real Madrid players were able to push upwards when they had possession. That left a lot of space for Timo Werner and Christian Pulisic to run on to if a ball came forward. That is also likely why Tuchel went with his most forward thinking passers from the back.
If those long balls were on, Chelsea would shift into their usual 3-4-3 or a 2-3-2-3 pattern. This was achieved by essentially having two separate pendulums. Mount would move up to join the forwards as N’Golo Kante and Jorginho would shift over to cover. Often at the same time, Azpilicueta would push up high on the flank and Andreas Christensen would push up higher and wider to cover him in the event of a counter. Antonio Rudiger and Thiago Silva would then shift over to cover just like the midfielders did.
Perhaps one of this disadvantages of this movement is the onus it put on Kante to help with transitions. He would often find himself the man most central on the attacking side for Chelsea and while they left he well poised to use his dribbling ability and tackling, it also required him to do passing to which he is not as suited as Jorginho or Mateo Kovacic. If Kovacic is fit for the return leg and Tuchel uses similar tactics, it wouldn’t be surprising to see one or the other take Kante’s role instead.
Tuchel’s done a lot with a squad that isn’t always comfortable with what he’s trying to do. The main thing is the Blues were able to whether that storm that surrounded Karim Benzema’s goal. 1-1 is a narrow advantage heading towards Stamford Bridge, but an advantage nonetheless should Tuchel be able to outwit his opposition once more.