To be honest, the 4-3 game in the final set, where Rune had a break point, was the one point in the match it looked like Sinner was actively trying to throw the game but Rune put a second serve return wide and the rest is history.
I know it's not the best attitude to intentionally tank a game but if you're going for, say, an Olympic Gold on clay and you have a chance to knock Rafa Nadal out by tanking a meaningless match, do you do it and maximise your chances of winning? Anyway, fair play to him to back himself to beat Novak, it was never really going to happen in a final here though.