Lionel Messi (#10), whose normal area of the pitch is just above the penalty box on the offensive right side, has drifted over to the left corner of the penalty area. The second-to-last defender has gotten too deep, allowing Alexis Sanchez (#9) to be on-side in front of the goal.
The defense, busy with Iniesta and Sanchez, seems surprised to find Messi on the left. Even the announcer in the commentary from which these screen shots were taken initially states Iniesta's pass is back to Alba.
Three defenders dash toward Messi as he pushes the ball forward, leaving Iniesta all kinds of space on the offensive left.
A defender attempts a tackle (a technique for dispossessing the ball from an opponent)...
...but Messi swiftly moves the ball around the threat with his left foot. The backing defender puts his foot up in case Messi attempts a shot toward goal.
Taking advantage of both defenders reacting, Messi deftly redirects the ball with his right foot...
...and squeezes it between them.
Messi follows the ball, but then makes himself big and slows, knowing if a defender eager to chase him down from behind bowls him over, Barca will be awarded a penalty kick.
A look at the big picture gives a clue at Messi's true objective.
Messi moves to position himself in front of goal and leaves the ball for Iniesta to receive.
The three defenders that were collapsing on Messi moments ago are now completely irrelevant.
Iniesta maximizes his options by pressing toward the goal-line.
Iniesta prudently decides to slip the ball back to Messi.
Messi swings his deadly left foot toward goal.
But only nudges it into his right foot.
The ball bounces back to under Messi's left foot, which he reloads with eye-blinking speed as the defender, reacting to what he expected to be a strike, falls to the ground.
This time Messi does crush the ball, at point blank range, into the net.
FC Barcelona is almost always exceptional at exploiting spaces, but they sometimes forget how disrupting little things like switching positions on the pitch can be. Barca is going to have to remain inventive in order to win the treble this year....
