Slavia Prague pressed high and with great intensity throughout the first half, causing Chelsea a lot of problems in buildup and limiting them to very few opportunities to break through and enter the final third.
From their diamond, Slavia’s front two either pushed through onto back passes to Kepa (forcing Chelsea to play short into pressure or attempt long balls) or pressured Chelsea to one side of the pitch where they could shift their midfielders over as well to apply pressure in the corners.
Slavia often won the ball in midfield and would attack the wings through their strikers making wide runs, the fullbacks moving forward, the wide central midfielders making runs from deep and joining the box (especially Traore), and Stoch having freedom to drop deep to collect the ball and move wide to create overloads.
Chelsea also had difficulties pressing and recovering the ball in higher positions, which again meant having to drop back around their own penalty area to defend and recover the ball. Although this provided Slavia a good platform to keep the play in Chelsea’s half, Chelsea’s deep defending was strong enough to limit chances from open play and not fall behind in the game during periods where Slavia were at their best.
Where Chelsea had more success with the ball was when they could break through pressure to find Willian facing play in the final third, and finding the fullbacks advancing into space from midfield. Anytime Willian would receive the ball facing Slavia’s backline, he would be 1v1 against the fullback and he could instantly create an opportunity, since Slavia’s midfield would be stretched from pressing high and their backline dropping back to defend their own box.
When playing with possession from midfield, there was little room for Chelsea to play through the middle, but opportunities would arise for the fullbacks when moving forward with the right timing to receive passes from the central defenders. Slavia set up to cover Chelsea’s three central midfielders with their wide midfielders, with Stoch on Jorginho, leaving Kral spare as cover behind them. With the front occupying the center backs, Chelsea’s full back were both left free to and could be found with long diagonal switches, which created opportunities when used.
Chelsea had much more success in the second half, where they were closing the distances better to press higher up and were thus able to win the ball higher up. They would also not face the same intensity of high pressing by Slavia — very hard to keep up that level of intensity for the whole game — so Chelsea were much more successful in finding the spare man to advance the ball into midfield from deep buildup, and were able to play most of the half with possession in midfield. Chelsea’s main concern in the second half was losing the ball in midfield and leaving space to counter, as well as the set pieces into the box which would follow the attacks.
With Hazard’s arrival, Chelsea had a player consistently moving inside into midfield to collect and keep the ball under pressure, allowing them to push forward into the final third to attack — Alonso also joining the box more often when Hazard remained wide on the wing. The latter would see Chelsea take the lead late on in the game, with Willian receiving the ball on the right facing Slavia’s backline, using the run of Kante to create space on the ball, and playing an early ball into the box for Alonso to finish.
xG map for Slavia Praha - Chelsea— Caley Graphics (@Caley_graphics) April 11, 2019
Another defensive away performance by a favorite, this one worked pic.twitter.com/bchMShJ4Gg
Slavia’s pressing and high positioning during the first half caused Chelsea a lot of problems. Chelsea made many errors with the ball to give possession away, couldn’t close the distances to press high without the ball, and had to defend and recover the ball in deep positions. In the second half Chelsea played higher up (Slavia couldn’t press with the same intensity as they had in the first half), which allowed them to create more chances from the wings, and win the ball higher up — where they would score a crucial away goal late on in the game to to go into the second leg with the advantage.