While Djokovic and new world number one Andy Murray look set to dominate in 2017, the likes of Thiem, Germany's Alex Zverev, Australian Nick Kyrgios and several others are beginning to make inroads into the top echelons of the game.
Nishikori's movement was sharper and his ball-striking cleaner, and he earned his rewards with five games in a row to win the first set. The world number nine wasted six set points and saved one before finally sending shockwaves around the arena to take it 12-10.
It was all downhill for Thiem, however, after that.
The first set was tight, with only one break point apiece, but with Thiem finding a good rhythm on his potent single-handed backhand it was the Austrian who dominated the tie-break, even if he took his time clinching it.
"Dominic started very well and he definitely deserved the applause", said Djokovic. I had only one set point. It's going to be a good first match.
A few weeks back, the WTA Finals in Singapore came to an enthralling end with a resurgent Dominika Cibulkova summing up her most consistent season by beating new World No.1 Angelique Kerber to lift the WTA Finals trophy.
The 29-year-old remains on track to achieve that target despite a shaky first set in the opening match of the prestigious season-ending tournament at London's O2 Arena. "I think with my own game that has helped to be more consistent week in and week out".
"I felt more comfortable".
"I saw the work he puts in every day and I'm really impressed the way he's been playing the last couple of months".More news: Hamilton wins in rain, forces title showdown with Rosberg
"I thought we played on a high level", Djokovic said right after.
Chasing the world number one spot has been the driving force and it would be a supreme effort if Murray were to come to the O2 against numerous world's best and win a first World Tour Finals title.
The Scottish star became the world's best player last week and must match or better Novak Djokovic's performance in London to stay top of the pile.
"It was a very good and very intense first set", Thiem commented. "After the first set I lost a little bit of energy which is required to play against Novak". He was playing well. I heard also that Basel was also quite fast.
He lost all three matches in 2014 but is in the sort of form that can give Murray cause for concern as the pair begin their campaign.
"The crowd was very nice".
"For me it was always a dream to be play in the Tour Finals. I value them as the highest goals and ambitions of myself". I was sitting at home watching when they played in Cincinnati, so that was okay.
"It was just a nasty cut that I had when I didn't manage to return the serve, the first serve", Djokovic said.
Murray will be keen to improve on his seven appearances at the season-end tournament where he has only got out of the group on three previous occasions, the last of those coming in 2012.