I was definitely rooting for Thiem yesterday, for a number of reasons. Some of them are personal: e.g., I've spent a lot of time in Austria over the past six years and have friends there who obviously root for him, and I commentated on a great Thiem-Coric match at the ATP 1000 tournament in Madrid a few years ago and have been following his career particularly closely ever since. (He's now the first player male or female to win a Slam after being involved in a matched I'd called.) But there were two entirely tennis-related reasons as well: one of them is that I don't think Zverev deserves to win a Slam yet. No player with his balky serve should be winning Slams, and if he'd had to face someone like Medvedev in the semis instead of Carreno Busta, there's no way he would have reached the Final. (And Carreno Busta came very close to winning as it is.)
The other is that I think Thiem has done the hard work and has a CV which makes him a worthy Slam winner...but if an attack of nerves had caused him to lose this match - and apparently he attributed both his horrible play in the first two sets and his cramping/choking in the 5th set to nerves as well - it might have had a devastating effect on his career. Instead, he's the first NextGen player to get over the Grand Slam hump, and even if it came in a tournament with no Federer, no Nadal and a defaulted Djokovic, it's still a Slam, and I think it will give him confidence and help him play his best tennis the next time he faces one of the Big Three in a Slam, in a Final or otherwise. (He's a bit like Andy Murray in that regard, Murray having had a 0-4 record in Slam finals before finally winning one and then going 3-4 in his next seven Slam finals, the latter being a perfectly respectable record in the Big Three era.) If Thiem should play Djokovic or Nadal at Roland Garros in a few weeks' time, we might see some amazing tennis. And my hope is that Thiem being successful will inspire Medvedev and Tsitsipas and indeed Zverev, et al., to raise their games in such a way that maybe the NextGen will be enough to help men's tennis survive the inevitable departure of the Big Three era, or indeed to give Djokovic some serious competition after Federer and Nadal leave the stage first.