"I think clearly I played a great match today", Dimitrov said.
Dimitrov, playing the season finale for the first time, joins Group Boris Becker victor Roger Federer as the only unbeaten singles players, and the Bulgarian will fight for the champion berth against American Jack Sock on Saturday.
"It is the best win of my career, for sure", said Goffin, who lost all six of his previous encounters against Federer.
"I was telling myself try to relax a little bit, there's so much pressure on every match in the season because if you lose you go home", Federer said in his on-court interview after the game. It paid off. I started to serve well. At 3-0 in the second set, Goffin was digging his heels into the game.
Goffin needed just the one break in both the second and third sets and displayed a previously unseen grit to deny Federer his lone break point opportunities in either set.
While his journey came to a halt, the 25-year-old said he now felt like he belonged at the top of the game.
The match was typical of Goffin's inconsistent week on his full debut at the tournament, after he played one match as an alternate a year ago.
"It was the first time against Rafa".
The first set went with serve all the way through to 6-6, but the seven-time champion never really looked to have turned on the gas; throwing away easy points with careless backhands into the net and then dropping in a few casual aces to keep the scoreline ticking along.
The world No. 2 had secured his path to the last-four by Tuesday night, having beaten Jack Sock and Alexander Zverev, and he made it a clean sweep with a win over Marin Cilic on Thursday as he looks to win his seventh season-ending title.
Dimitrov ensured he'll end the year at a career-high No. 3 after coming from behind to defeat Sock.
Dimitrov is the first debutant to reach the final since David Ferrer in 2007.
But Goffin gradually found his way back into the match and ended up winning 12 of the next 14 games. "But my belief was so good today and I'm glad I managed to win".
"I'm going to have fun, play big, play free".