Swansea opt for a closed block with the ball
During the first half Swansea circulated the ball between the back three and the midfield diamond outside of the Chelsea block. The wingbacks were in midfield, while Llorent was the only man on the last line. Sigurdsson would move between lines and drop deep for the ball, while Cork, Ki and Fer would move to receive the ball in front of the Chelsea block.
When Swansea were building in deep areas there were moments where the Chelsea midfielders (Matic and Oscar) would move up to press high. In some of these situations Cork would move deep to join the defensive line, before they would look to find forward passes to the remaining three midfielders. When not under pressure Cork would either play short passes or a diagonal to Taylor on the left, while the wide central defenders would both try to play forward passes, mostly up to the wingbacks--pressured upon receiving the ball and few options.
Some combinations between Sigurdsson, Llorent and Fer were attempted as they approached the final 3rd, but they were unsuccessful in execution. The few occasions Swansea were able to get the ball into the Chelsea box were from crosses, long throw-ins, and, on one occasion, an early pass to Llorent (with back to goal) inside the box--he was marked tightly by the Chelsea centre backs and unable to retain the ball.
When Swansea lost the ball in the Chelsea half (after a long throw-ins etc.) they would press high. One of these situations was almost advantageous for them, when Willian had the ball on the right. Here Ki moves up to block an option near the ball, while Fer (out of sight) is anticipating the square passes to Terry on the far side.
When they were within range, Swansea would continue to use the wide central midfielders to move up to pressure the ball throughout the match, especially after the change in formation.
Chelsea aggressive and fast with the ball
With the ball Chelsea were able to switch the ball to the wings early and effectively. In particular, attacks which start from the left and end up with a switch to Willian 1v1 around the box are very dangerous, as Willian can shift the ball quickly either side and shoot powerfully towards the far post. When they were unsuccessful in their attempts to get into the box from these situations they were either prevented by being overloaded and isolated (Hazard and Costa the only players in the early attack) or they would be fouled by a Swansea player.
If they were unable to immediately create these situations and delayed with the ball they would bring the wide central midfielders and fullbacks into their possession game in the final 3rd. On the left Matic was much more involved in higher areas than usual, while Azpilicueta was overlapping when possible. On the right they had the usual combinations and movements between Oscar, Willian and Ivanovic, albeit with more focus on Ivanovic and Willian up the wing than Oscar going behind centrally--as in previous matches.
During possession in deep areas they continued to pass the ball through the lines and play through pressure. They play forward through the fullbacks and the central midfielders. The fullbacks will pass to the near side winger--Willian drops very deep and turns inside, while Hazard remains higher up. Kante can also play diagonal switches to the wings, while Oscar and Matic drop deep along their line in order to collect the ball and play forward.
Holding the ball in deep areas and inviting pressure allows Chelsea to open spaces and break Swansea’s defensive lines, while they are then able to create situations to play to Costa, Hazard and Willian behind the Swansea midfield line and run with the ball at the last defensive line.
Chelsea were also able effectively regain the ball quickly in high areas when they lost the ball. Any first time or early short passes into midfield were pressed aggressively, and often recovered by the midfielders--especially Kante.
Just before halftime Guidolin made a change, bringing Barrow on for Taylor. This was a tactical change in order to revert back to the usual back 4, where Naughton went back to right back and Kingsley shifted to his familiar left back position. With the ball Barrow would play either on the right wing, or inside to support Llorent on the last line. Sigurdsson would move freely along the line at the top of the diamond with the ball--joining the right of the field with Barrow, while Llorent would also move over to create potential overloads on the last line. Defensively both Barrow and Sigurdsson would drop back to the wings to create a 4141, and the central midfielders would continue to pressure higher up the field.
Barrow’s introduction aided Swansea in the final 3rd, especially during counter attacks. Not only did he add the extra support in high areas, he is also a player that can carry both dribble with and carry the ball forward, which is something they starting lineup lacked. Later on in the game, both Barrow and Naughton were able to receive the ball high on the right, before crossing it into the box.
After Swansea took the lead, the amount of transitions increased. Chelsea moved more players up into high, central areas--both in and around the box. Oscar was playing higher and mostly inside the box, Ivanovic joins and stays in the box, while Hazard moves inside to get onto the ball more. Moses was very direct and tried to take on his opponent at every opportunity in order to try to create a chance, while the introduction of Fabregas brought his excellent passing game to Chelsea’s offensive play. Not only was his pass into the box crucial in creating the equaliser, but his quick and long passes behind the defence during counterattacks are something that only he can consistently perform in the Chelsea squad.
Chances from set pieces
Another area where Chelsea were able to create good chances with the ball was through set pieces, especially during the first half.
From corners Oscar was free yet again, while Swansea were in a similar setup--Barrow short, Fer and Llorent zonal, Naughton and Ki cover the edge of the box, and everyone else man-marking. On this occasion Terry loses Amat (through movement and blockers) while Costa is able to receive the second ball at the far post.
After not taking advantage of the offensive set pieces, Chelsea had some problems from counterattacks later on. Swansea were able to counter from a defensive free kick to win the penalty (Barrow and Sigurdsson both countering from the wall), while they created another counter (Barrow using his mobility) after a long throw-in towards the end of the game.