This a situation where the blue dots has the ball, imagine the rest of the red team behind the opponent (O) who’s the nearest to the ball and then is expected to press (or at least close the passing angle, it depends of what the manager wants).
(A) has the ball, im my example this is Mikel. He has one passing choice to progress forward, this is (B) because (O) could easily intercept a pass toward (C).
Mikel (A) has two ways to pass the ball to (B).
Mikel (A) passes the ball straight to (B) before being really closed down by (O). As a result, (O) can turn around easily and close the passing angle between (B) and (C).
Then (B) has the only choice to pass backward (yellow) ((B) doesn’t necessarly knows what happens in his back, especially now he has the ball and that the closest player around him has to close him down, this very player may be just behind (B)).
If (B) is static and that (O)‘s team has chosen the tactic not to press but to stay organised (that’s what Chelsea face most of the time), Mikel will play backwards because considering (B) doesn’t drop from his position to ask the ball (the Blues’ off the ball movements are very poor), he’ll face a situation where he’ll have the ball without movement around him, facing an opponent’s line of players (likelined to a wall). There, (O) won’t go upper, he’ll stay where he is and close the passing angle (in red)
Then, Mikel’ll be forced to play backwards (in yellow). The most important thing is to keep the ball and not attempt a stupid chip or whatever to no-one and then give the ball away.
Lucas Leiva got very criticized at Liverpool in the past because he gave the impression to be vulnerable because of his slow execution. Despite the instructions being given (press or stay organised), some players are then eager to think that they can regain the ball with an explosive pressing.
That’s where Lucas or Mikel uses one of their skills, technically they have an excellent short passing game. I mean by “excellent” the fact that the pass is quick and precise (at this level, players usually give each others cannonballs, that’s easier to control than a weak pass).
Mikel’s trick is to release the ball just before being closed down ; it requires a high level of self-confidence and of course, excellent technical abilities. By keeping the ball one could regard as “too much”, (O) will be tempted to speed on Mikel. Then Mikel releases the ball to (B) who has the passing angle now open (in green) and can give easily to (C)
What makes the difference is that pressing an opponent is different from closing down a player. Here, (O)‘s task is to reduce the opponent’s passing choices (quite often the way teams we face plays). When (O) sees Mikel giving the impression to be “unconfortable” with the ball, it triggers (O)‘s pressing.
That’s what creates the inbalance from a situation where there shouldn’t be.
Items of conclusion
We can wonder why Swansea passed that much often the ball between Vorm-Williams-Britton-Rangel-Williams and so on just in front of their own penalty box… (33% of the time in their own half, 2nd highest rate). That’s their way to force the opponent to come out from his position and then counter attack them.
Here, Mikel can help his team to break teams who plays Chelsea with the clear intent to stay organised.
Playing possession football in the opponent’s half only can be efficient when you’ve some penetration skills like Iniesta’s or Messi’s with Spain or Barcelona. Otherwise that’s almost a way not to conceide a goal: defense via possession by keeping the ball far away from one’s own goal.