Selby recovered from trailing 4-1 and 5-4 to outlast the 2006 world champion Dott, who saw the match begin to slip away when he jawed a tough cut on a black for a 5-1 lead before world number one Selby potted it to trail 4-2.
A break of 53 by Selby after Scotland's Dott had missed a black early in the final frame was enough for him to stagger over the line at 12.29am on Sunday, the day of the final, in a turgid contest that began just after 7pm on Saturday with the average frame time over 25 minutes.
In a match that was broadcast live on terrestrial television, Dott felt that he was not the only loser from the evening's goings on.
German Masters
Murphy and Ding lose German Masters qualifiers as shocks continue
"Missing the black has probably cost me the match," said Dott. "If the black goes in, I go 5-1 ahead and wouldn't lose. But after that, he just bored me to tears.
"I felt that I was living in a nightmare. I don't know what the stats were, but I'm guessing that even in the frame I won my highest break must have been about 12. I just couldn't get in the balls. Either the red was safe, the black was safe, the pink was safe...I was finding it hard to stay interested.
"I'm not having a go at him. He is without a shadow of a doubt the best in the world at frames like that. I just find it hard to play them."
The real winner from the evening is defending champion Neil Robertson, who booked his place in the final in the afternoon with a 6-2 win over Shaun Murphy.
Selby bids for back-to-back major wins in the sport after lifting the UK Championship last month while Robertson aims to join Cliff Thorburn, Stephen Hendry and Paul Hunter as the only men to successfully retain the invitational event.
"The Grinder" Thorburn celebrated his 65th birthday earlier this week, and this was almost like a return to snooker in the Canadian's pomp of the 1980s.
"It could be a long day tomorrow," said Dott. "I don't think that is a good advert for snooker tonight. That is just my personal opinion. I don't like being involved in games were lots of people are actually leaving.
"It is not so much putting me off. You just don't get rhythm. It is like killing the game. It is the equivalent of a football team putting 11 men behind the ball and not attempting to come out. It is just the way Mark plays.
"He enjoys frames like that, but by the time it reached 5-5, I had no rhythm whatsoever. I mean none. Almost like I hadn't potted a ball.
"I know Mark will say the balls went awkward, but he constructs the frames that way. And it was hard to get out of.
"In one of the frames I thought I'd just smash the balls up. Even in the last frame, I went for a long red that I potted that I would probably never have went for because I didn't want to get involved in a safety game.
"It might sound like I am having a go at him, but I am not. He is the complete opposite of Judd Trump, but Mark is not there to entertain the crowd."
Dott was boosted by winning an opening frame that he seemed destined to lose as Selby jawed the black off the spot on a break of 54 when poised to clear up.
Dott slotted the black to give himself valuable momentum.
Selby would level in the second frame with a 79, but Dott was clearly finding some form as breaks of 111 and 75 carried the man from Larkhall two frames clear at the mid-session interval.
Dott remained in the ascendancy to lead 4-1 despite a late scare when Selby managed to claw back one of the two snookers he needed with the blue, pink and black left on the table.
Dott finally potted the pink to scramble over the line and leave himself two frames short of the final.
It looked certain to be 5-1, but Dott saw a black agonisingly stick in the jaws of a top pocket after Selby had missed a fine cut on the pink.
Selby was punching the air after potting black and had more reason to celebrate when he came out on the right end of a scrappy seventh frame lasting 51 minutes - the longest frame of the tournament.
The eighth frame looked like being another lengthy affair when the reds were welded to the top cushion with the pink and black, but Dott threw in a series of errors to hand Selby the chance to restore parity at 4-4 which he duly accepted.
Some people had already seen enough as the ninth frame ran for an excruciating 46 minutes with Dott recovering from needing a snooker to force a re-spotted black after Selby had pieced together a run of 53.
Selby narrowly missed the black as Dott returned to pot black for a 5-4 advantage.
It was hardly a major surprise to be subjected to a deciding frame as the Scot missed a brown to a middle hole.
Selby leapt out of his chair to record a timely knock of 65 before emerging as the superior player with Dott frazzled.
"I didn't sleep great last night, and I felt very tired out there," said Selby. "It was very tough. I think we just brought each other down. I just kept digging in, and seemed to take it out of Graeme.
"In normal circumstances when I was 4-1 down, I'd feel like I could win. But tonight, I felt very flat.
"I will go into the final and enjoy it. I didn't enjoy that tonight.
"There is not much you can do. Sometimes there are great games, and sometimes it goes scrappy. That is out of my hands. You can only do what the balls do.
"Graeme played great before the interval, but afterwards it was really poor snooker."
German Masters
Williams, Trump suffer shock German Masters exits, Higgins and Murphy progress
German Masters
Hendry whitewashed by Stevens as miserable run continues
24/11/2022 AT 22:25