As
@rafanoy1992 points out, he got handed that first set. It wasn't that easy to lose it if it looks like a tank-job.
Now, when his back was bothering him into the 3rd he could have pulled back at let Rune have it, but what does that signal for the SF? He was playing a guy he'd never beaten in front of his home crowd...I just don't think he was going to lose on purpose. Rune could have obliged by beating him outright, but didn't have the "mustard." (A little joke for
@the AntiPusher.) I have a hard time blaming Sinner for refusing to fold. I can blame Rune for not playing better.
Sure the odds are against Sinner beating Novak again this week. And, as
@nehmeth pointed out above, Novak looked the best he has all week today, by far. Must have gotten over that cold. But Sinner is playing great tennis this week, he's undefeated, is good indoors, and has the home crowd. I think his winning ways may serve him well.