We have a debate in the spanish forum about the Diving Tackle plus Shadowing combo and we will like to have an official clarification.
We've two options in here.
First is you can use them in the order you prefer. I mean, you can try to shadow the opponent first, and if you fail, then you can use DT to knock him down.
The other one, and i support

The different arguments came because some argue both skills are triggered when the opponent tries to dodge out, and I support the fact that shadowing is ONLY triggered when the opponents dodge successfully.
For us, as non english natives the rulebook is not really clear on this point, so any clarification will help