You can certainly cast Optus Sports from your laptop using Chromecast or Miricast.
Please bare with me as I am not too up to speed with all this but how do I do that?
When I watch U tube from my laptop for instance I see the little casting icon on the bottom of the video and I click on that to send to my TV chromecast.
But when I am in optus sport on my laptop I don't see the casting symbol on the video I want to watch.??
I can do it no problem from my phone
The easiest way in my opinion is to use google chrome browser. You will first need to pin the chromecast cast button as this link:
Then sign into optus sport on google chrome and click on the cast button, top right.
Hope this helps.
That's great, enjoy the world cup.
Thought I might add, you can cast anything now from your Chrome browser, all the catch up tv, photos and much more.