I've played Thresh quite a lot and is my most played support by far. Honestly it's really hard to comment on a replay of a game that was so one sided so no comment on that but I'll tell you how I like to play Thresh. Try it and see if it works for you.

I recently became a fan of the new NA LCS team Renegades and their support Remilia is known for her Thresh. I tried this rune page that she uses and it was today actually that I felt a difference. It probably doesn't matter that much but it does make autos feel smooth. Check her stream when she plays Thresh maybe, it's a work of art.

I like to play Thresh as tanky as possible, frontline and take as much damage as I can for my team. For masteries everyone tends to use 0/9/21. I like to use the one that was popular awhile ago, 0/16/14, 7th page.

Fair warning that from here on out it's my own personal stupidity when it comes to item builds. I almost always build Merc treads. It's probably better to build Mobi boots but I'm stuck in my ways, and again I like to play really aggressive and tank for my team. I can't count the number of times that an enemy Thresh has walked up tried to catch someone with a hook, misses, and gets CC'd and killed in 2 seconds while his team stands around. I just love Mercs because they help forgive mistakes like this which I make a lot of. I almost always upgrade to Face of the mountain first after sightstone with the occasional switch to Talisman. After that righteous glory if the game is going well so that it's easier to engage and close the game as fast as possible before NA throws occur. If they have too much cc to handle Mikael's 2nd is great if you can use it properly. Not a lot of people buy Locket so I'll usually grab that after righteous. These 3 items are interchangeable and I usually switch up which I build after FoTM based on the game.

Take what I say with a grain of salt, I'm only Gold I but what I said usually works for me :D