As PL says, there were some big swings in those 1970s World Finals. I think Charlton was the kind of player that if he got on a roll he could easily monopolise a session. You could be frozen out for an hour or so at a time, by which point your cueing might have deserted you. That, and Reardon said he disliked morning sessions, which I think started as a half-joke to play up to his 'vampire' image, and that he began to believe it in the end.
The ’75 final was probably as dramatic as any finish the game has produced. Reardon won a number of finishes on the colours, and a re-spotted black, as Charlton collapsed… Collapsed literally, according to Reardon in the final frame: https://www.youtube.com/watch?v=T8Bgf-ysZdo
I think the final frame was a little more cagey at the start than Reardon acknowledges, and that he embellishes somewhat. This report suggests a bit more happened, based on the frame scores. The report shows a few diagrams of key shots, including the brown I mentioned, which would’ve put Charlton 30-25 up.