Quick story: two seasons ago, I matched up against Teferi Nexus as RB Aristocrats. I won game one. Opponent combo'd off in game two and eventually established two Teferi emblems. It took so long that I decided not to concede and just let their clock run. (Chess clock times when they combo'd off: me at about 23:00, them at 21:00; times when I came close to decking: me at 22:40, them at less than 9:00).

But opponent's win con was to discard the Nexus, and perhaps didn't know how to Teferi tuck into an empty deck. After getting two emblems, they killed their Tamiyo to pick up an Absorb. Then they had big Teferi without enough loyalty to tuck. With about two cards left in my deck, I got to hit them with Swamp then Duress, breaking their ability to discard Nexus to hand size. With an empty deck, they couldn't draw without putting a Nexus into library. Opponent panicked, couldn't figure out how to loop Nexus properly to get Tef's loyalty high enough to start tucking, and promptly decked themselves.

Never give up.