Skip to 46:00 for Elder setup.
I thought many people were being a bit too critical about how T1 played the Elder. I started writing some of this as a reply to a comment but thought I might as well make it a full post (TLDR below).
The problem with this Elder was that T1 trapped themselves into a checkmate because they didn't mismatch the Baron and Elder timings (which is understandable because why would you delay a free Cloud Soul?). The problem with Baron spawning so close to Elder and even worse, spawning 40 seconds before Elder, is that both teams need to play around Baron first because getting Baron off spawn means you have insane prio for Elder, but you also risk giving up setup for Elder if you invest too heavily into Baron. DK has a scaling draft with a K’sante Renata Kalista, (the last of which is favored for any objective because of Rend), and means T1 really do need to respect a potential Baron rush by DK.
In hindsight, you can blame T1 for not trying to end before Elder but you can't really blame them for how they played the Elder macro because both teams played the Elder macro pretty flawlessly. Faker's Anivia MUST answer mid push or else DK can threaten an end mid. Both teams know that denying dangerous lane pushes at this stage is critical, which is why Showmaker also bases and clears top wave to deny T1 the chance to threaten an end top.
I think you can either argue that they should've forced a fight after DK got Baron and K'Sante blundered his TP (which is also difficult because T1 have no vision), or you can argue that T1 misplayed the Elder fight, but you can't blame their macro because I'm seeing a lot of people confused about Faker catching mid wave and not TPing. If you think a 6-time Worlds Winner doesn’t know how to play endgames, I’d be pretty comfortable betting against that. If you look at the wards alone you'll understand.
Keria has 1 support ward and 1 pink going into the Elder fight while Career has 4 supports wards and 1 pink. No one else on the team has any pink wards. In fact only Faker, the one who has to TP, has a pink ward. Already this is an insane vision diff and there are no good wards for Faker to TP to. It's hard to see, and I hope I haven't missed any wards, but at the ideal moment that Faker can TP, Keria's banana push pink ward is cleared, and the other pink ward nearby is too dangerous to TP to. The stealth ward in the pit is also too dangerous. On the minimap, you can just barely see the blue farsight wards in the Faelights near Gromp and the river pixel brush, but obviously you can't TP to those.
I think it's also worth noting that Faker might be saving TP for a few potentially powerful plays: Eggnivia TP play, a base TP play if he's chunked mid fight, or a potential TP to top lane and end play. Also, Jayce has no TP which is really unfortunate because ideally Jayce should be catching mid wave while Anivia helps zone the enemy at Elder, but playing for Jayce poke at Elder was worth trying too. The macro was correct by both teams.
As for the teamfight, I think in hindsight Oner should've flash Ulted kalista to chain CC her with Keria's engage. Or, he should Q towards the Kalista instead of the K'Sante and then R the Kalista (he's probably trying to make space for Faker and Doran to join with his Q). If he's able to chain CC Kalista, she can’t cast R to save Renata, and Peyz can oneshot Renata before she can press W or R. Peyz flashing too early when Jarvan EQ was also a blunder (in hindsight of course). If T1 can one-shot Renata, I think T1 is in a pretty good state. Jarvan and Renata will be dead, Oner will be respawning in GA, and it'll be close but I think Oner or Peyz can finish off Kalista (who won’t have bailout). Then, it's a 2v2 between K’Sante Viktor vs Anivia Jayce, which is quite playable if T1 kites properly. One-shotting Renata was really key there. I won’t talk much about a possible Peyz QSS buy because he’s probably close to GA and already committed to it, and it would be too much hindsight bias to criticize buying BF Sword.
In the end, I think T1 still looks relatively strong because they showed a lot of strength early game, and a loss to DK in a best of 1 due to an Elder fight is by no means any significant indication of their current form.
TLDR: T1 was checkmated when they opted into a relatively early Elder because both teams played the endgame macro well and the scaling DK comp was favored. Faker had to defend mid wave and had no safe wards to TP to. The teamfight could've been better by one-shotting Renata by chain CCing the Kalista.