Sunday’s Game of Thrones episode was epic in just about every conceivable way, including, it turns out, the Nielsen ratings. Per the measurement company, “The Spoils of War” drew a stunning 10.2 million same-day viewers for its 9 p.m. linear HBO premiere — the biggest-ever initial audience for the series. The episode, directed by GOT newbie Matt Shakman (It’s Always Sunny in Philadelphia), surpasses a record set just last month by GOT’s seventh-season premiere, which drew an overnight audience of 10.1 million viewers. The actual audience for both episodes, however, will end up being much bigger: It’s likely a couple million more viewers caught the premiere via HBO’s digital platforms (HBO Go and HBO Now) or through cable on demand. Those eyeballs, plus the millions more who’ll watch via DVR or replays on HBO’s various linear channels, will probably push the actual audience for “The Spoils of War” over 20 million within the next month. As Jaime Lannister learned the hard way, never underestimate the power of dragons.