Diagram:
This try was the first against Scotland. It was a very well-executed try. Note how they use forwards and backs together. It didn't matter what number was on their backs, their movement and skills were all excellent. The accuracy and composure to execute was top drawer. Befitting of a team that wants to be the best in the world.
Part One
Here we have 19 as first receiver with a pod underneath him. 20 runs a hard line to the defensive front, which commits them to stand flat, as 19 rotates and slips a short ball to 10. Notice how they have 14 standing right against the touchline. The edge defender is marking up on 6 who is deep, and the lone Scot wing has to make a decision here to protect the edge defender, as well as mark up on 14. The deep cover for Scotland is tracking on the inside of 6. They are essentially ready for an overload on the edge defender, and protecting him on the inside and outside.
Part Two
Here we have 10 with 15 and 6 underneath him. He moves diagonally up, committing the defensive front. He has 5 on his outside who also runs a hard line, and this helps hold the defensive front in check, as 10 sends a short ball to 15. When the lone Scot win starts to track inside, 14 raises his hand and calls for the ball. The Scot has a lot of space to cover now.
Part Three
Here 15 runs a hard diagonal line up with 6 outside him. He has options, he can go it alone, commit the edge defender and slip a short ball to 6 into space, but he chooses to send the long ball out to 14. The Scot win has committed to this dangerous situation on the edge defender, and the Scot tracking behind the line is also focused on a breach here. The Irish really have the upperhand here no matter what the Scots decide to do.
Summary
Notice how the Irish setup very quickly. They are so fluid moving in and out of units, it's actually wonderful to watch. I haven't seen another international side coached with so much care and attention to detail. They are smart players, and very disciplined. Lots of composure. There's a purpose to every unit, every run, and every pass. They aren't simply lining up in clunky layers, as I have bemoaned under Erasmus, but they are setting up each layer of attack for success. Every ball carrier has options, and at least one support runner. It takes the heat off of the individual and is continually forcing the defence to make many decisions with each pass and run. They aren't passively running, and they are not moving through each phase of the attack whilst allowing the defence to slide and track the width of the field with them. This try was a masterclass in how to integrate backs and forwards, dominate key areas of the field, manipulate the defence, and create space. If there was one play I could have at hand when sitting Erasmus down to teach him, this would be it.