Higgins is through to the quarter finals after beating fellow Scot Dott and keeping up his excellent record since returning to competitive action - he has now won 15 of his last 16 matches (Rob Hayes writes).
The match was finely poised at 4-4 heading into today's concluding session, and Higgins made the perfect start, knocking in a break of 79 in the opening frame. However Dott was clearly prepared for a battle, and he won the next two to take a 6-5 lead.
Higgins racked up a 53 to claim the 12th frame, but Dott responded immediately with a solid 50 then shared the next two scrappy frames to lead 8-7.
Dott looked to have the match wrapped up in the 16th frame with a clear chance in among the balls, but he left a red in the jaws on 44, and a grateful Higgins snapped up the opportunity, making a cool 79 to force a decider.
The two-time UK Champion knocked in a 56 in the deciding frame before missing a mid-range red. But Dott also missed a tricky red and Higgins added the points he needed.
"I knew it was going to be tough," he said. "It turned out just as I expected. It's good to know you can still do that under pressure, but there are some times that you crack, like I did at the Crucible this year against Steve (Davis).
"Stephen (Maguire) had a great result against Mark Selby, but I'm not even thinking about the draw. You just go out and play and hope for the best."
Northern Ireland's Allen reached his first UK quarter-final with a nail-biting 9-8 victory over defending champion Ding Junhui.
Allen had a commanding 6-2 lead overnight, but saw that slip away as China's Ding knocked in breaks of 78 and 103. Allen should have won frame 11 but missed the final pink and Ding won it on a respotted black to close to 6-5.
Allen won the next, before Ding battled back to 7-7. The next two were shared to set up a tense decider. Both players had chances, Ding making 35 before missing an easy black, trying to split the reds. Allen eventually got among the balls and made a match-winning 40.
"I expected Ding to come back at me today because that's what all great players do," said Allen, who beat Ding in the final of the invitational Jiangsu Classic last year. "I played so badly today I was lucky to get to a decider.
"I said before the match that Ding lets his head go down when he's behind, but that wasn't the case. I'm delighted to beat him because he's won this twice so it's a major scalp."
Maguire also fended off a fight-back to score a 9-7 success over Mark Selby. Leading 5-3 overnight, Glasgow's Maguire extended his lead to 7-4 with a top run of 72, before Selby hit back to 7-7 with 75 and 51.
But 2004 UK Champion Maguire proved stronger at the business end, with a 56 to go 8-7 ahead then a glorious 135 total clearance to finish the job. He now faces friend and practice partner Higgins.
Neil Robertson kept up his bid to add the UK title to his Betfred.com World Championship and 12BET.com World Open crowns by beating Andrew Higginson 9-5.
Down 7-1 overnight, Higginson battled impressively today with breaks of 75, 86, 107 and 60 to win four of the first five frames. But Robertson held his nerve and made a smooth 77 in frame 14 to settle the result.
"I played a silly shot when I was 7-0 up last night, I thought it was showtime," admitted World No 1 Robertson.
"Things started to go wrong today and Andrew played fantastically well. But I still had a big lead and even it had gone 8-8 I would have felt comfortable and confident.
"In a way it was good to be tested, rather than just breezing through my first two matches."
Robertson insisted that he does not feel his chances of winning the tournament have increased with the exit of Ronnie O'Sullivan. "I'm probably one of the few players who doesn't mind playing Ronnie," he added. "The hardest pressure to deal with is when you are the favourite, I've found that in some of my finals."
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