The Nuke had earlier breezed through world champion Luke Humphries and the ever-dangerous Michael van Gerwen en route to his maiden nightly triumph in the competition.
Catch up on all the action from night nine in the Premier League:
Final
Luke Littler (#28) 6-4 Nathan Aspinall (#4)
Luke Littler started the final with a storming 136 finish and was particularly close to a spectacular continuation of this dream start a leg further by missing the bull by mere centimetres for a 170 finish. However, The Nuke had to leave the second leg to Aspinall and was then immediately broken by Aspinall, who earlier this year took the day's victory on evening 5.
Aspinall then also retained his own leg and, without throwing spectacularly, looked to be in contention for another day's victory, but was briefly put in the way again by Littler, who set off a small laugh among the crowd after a somewhat missed arrow on D20.
With the score at 2-3, Littler returned to the match completely with a fantastic 125-finish on once the single and twice the double bull - his second 100+ finish of the evening.
The two consecutive leg wins and great finish seemed to have fanned the fire in the young phenom: from 1-3, Littler came back to 4-3 and had to take a scare when Aspinall was millimetres away from an equalising 88-finish, but the eighth leg was also a winner for Littler.
With victory of the day within reach, Littler still had to pull out all the stops to hold off Aspinall, but the Asp managed to quiet the cheering crowd and take a leg.
However, a very expensive bouncer with the chance of a finish seemed to throw a spanner in the works for Aspinall, who still had a chance to force a decisive 11th leg, but failed to take it from 113. A D10 finish failed, but the finish on D5 gave Luke Littler his first day's victory on evening 9 of the Premier League.
Semi-finals
Luke Littler (#28) 6-3 Michael van Gerwen (#2)
Littler lost the first two Premier League matches to Van Gerwen, but made the green wrecking ball bow out on evening 7. Night 9 started the 17-year-old with leg win on D5 after previously needing five arrows for a finish. Littler was a hair away from a very big 132 finish, but missed the double bull and thus had to leave the second leg to Van Gerwen after all.
The men then exchanged legs, but Littler distanced himself in the fifth and sixth legs against an unremarkable Van Gerwen, who seemed to have lost his momentum. Littler took a 4-2 lead and built it to 5-2 after a 110 finish.
Littler, who lost his only Premier League final to Van Gerwen of note, remained mostly subdued throughout the match and showed little emotion until the moment Littler made it 5-2. The cause could have been an incident during his walk-on, in which a spectator harassed Littler.
Staring in the face of defeat, Van Gerwen opened his counter-offensive with a somewhat exciting leg win after a finish from 16, but it was to no avail for the only Dutchman to come out in the Premier League tonight: Littler raced towards the end and finished it off with a 24-finish. For the second time this year, Littler gets to compete in the Premier League final.
Nathan Aspinall (#4) 6-2 Peter Wright (#8)
A match at a relatively lower level saw averages of under 90 after no five legs and a lead for Nathan Aspinall, who faced his third final this season. A strong leg from Peter Wright cornered the Englishman, but like a cat Aspinall jumped out of there with a handsome 121 finish.
A broken leg put Wright on a difficult three-leg deficit and with the final place at stake, it was Aspinall who finished the job in style with a bullseye finish after a lacklustre match. A clearly disgruntled Nathan Aspinall (93.10 average, 6/9 on doubles) was allowed to prepare for a final against Luke Littler and go on for his second Premier League day victory this year.
What Aspinall won it on were mainly the checkouts under 100: out of 6 checkouts under 100, Aspinall completed 5 of them, compared to 1 out of 5 100+ finishes.
Quarter-finals
Luke Humphries (#1) 5-6 Luke Littler (#28)
Luke Littler has a positive upper hand in mutual matches against the reigning world champion and did not take long to grab the first break of the match.
The 17-year-old phenom opened the match and held his own first leg before breaking Humphries with a finish on tops. But Humphries does not let one walk over him easily and breaks right back with stable throws.
A sloppy opening in leg 4 gave Humphries the chance to level the score and that's something you don't have to ask Cool Hand Luke twice, but then holding off Littler apparently did. A sloppy turn gives Littler the lead again in a match finished at a high pace and level, but Humphries answers with a bull finish for the equaliser.
Things keep swinging in Belfast with a leg win for Littler and a huge 148 finish from Humphries, who equalises again to 4-4 in legs. But again it is Luke Littler who takes advantage of a wavering Luke Humphries, who missed two darts for the leg and almost saw Littler fail himself but hit the last dart in D5.
With 108 on the board, Humphries had a chance to make things difficult for Littler, but the young phenom failed to get the job done, missing three match darts. Humphries made it exciting again and forced a decisive 11th leg en route to a possible fourth successive win over Humphries.
170 did not go out for Humphries and so Littler was allowed to try from 68. The Nuke finished the job and won for the fourth time in a row over Humphries, who failed to extend his run of three daily wins.
A very fast-paced match was decided by Littler mainly on the doubles, where Littler reached a percentage of 50% (6/12) after averaging 102.02.
Michael Smith (#3) 4-6 Michael van Gerwen (#2)
Michael Smith opened the match with a break point, but could not enjoy the first lead for long: Van Gerwen needed just 11 arrows to level the score with an easy 87 finish. Smith opened the third leg with five perfect darts and answered Van Gerwen's 11-darter with a 12-darter, which could have been a 10-darter.
Averages of 113 for Van Gerwen and 109 for Smith say it all: it promised to be a match at a particularly high level.
Smith was the first to really distance himself with the first finish in a leg of his own of the match: a finish on tops gave Smith the 3-1 lead after a mediocre leg in which both men struggled with finishes. However, an 87 finish in his own leg brought Mighty Mike close to Bully Boy again and put the score back to 3-2.
A more than mediocre start to Smith's leg seemed to put Van Gerwen in a perfect position to level the score, but both men were not having it and seemed impotent near the doubles. In the end, it was Smith who managed to find the score and restore his lead to two legs after a flurry of misses.
So how typical is it that the next leg sees a huge finish? An evenly matched leg that saw some pains copied from the previous one was decided by Van Gerwen with a huge 144 finish, putting the Dutchman back on 4-3. Smith seemed to have lost it completely for a while and so Van Gerwen smelt blood: the Dutchman needed two darts on D16, but put the score at 4-4!
It proved to be the recipe for Van Gerwen's first lead, who also took the ninth leg, winning three legs in a row for a comeback from 4-2 to 4-5.
Averages of 125 in consecutive legs gave the Dutchman great courage again and jacked up his match average, which had plummeted after a sloppy leg or two, to over 104. A hefty 150 finish was then the icing on the cake for Van Gerwen, who managed to win for the first time since evening 4!
Nathan Aspinall (#4) 6-5 Gerwyn Price (#5)
After the extensive singing of The Killers' 'Mr Brightside', the match could break loose at the SSE Arena in Belfast, Northern Ireland. And almost this went off with a bang: Aspinall had a 170 finish on target but missed the double bull by a hair.
However, the Englishman managed to make up for it and still took the first leg win with a simple 25-finish on the 18th arrow. After a fairly easy leg win, Gerwyn Price had the first chance for a break, but the Welshman failed to save it and gave the chance to Aspinall, who made it harder on himself than necessary with a dart into the double bull instead of the single, but a final dart into the D4 made it 2-1.
Tops put Price back on level terms in leg 4 with Aspinall, who has lost the Welshman's last six duels, but Asp put everything in place to avoid a seventh in a row: a finish in the single bull, which Aspinall now managed to find with some ease, put Aspinal back in the lead in this match from the bottom of the Premier League standings.
It was not until the sixth leg that the match saw the first 180'er from Price's hands, after which Aspinall threw in the second without thinking twice. Price used the 180 to fuel the first non-D20 finish of the evening: Price decided the sixth leg with a finish on D12 from 103.
Aspinall followed this up, as with the 180, with his first finish outside tops: a finish into the bull put Aspinall in the lead once again. With seven legs in hand, Aspinall provided the very first break of the match with a finish on D20, allowing him to start a potentially decisive leg.
Price, who needed two breaks to still win the match, grabbed the first of those two with a finish on D4 from 10.
With his own leg in the bag, after some stumbling from both sides, Price managed to completely turn the match around and the Iceman provided a decisive 11th leg. Facing his third win since evening 2 of the Premier League, however, Price (38% on doubles, 5/13) slipped anyway: with the Welshman stuck on 259, Aspinall (66% on doubles, 6/9) pitched his way to 64, from where the Englishman was able to pull the match to his own and maintains the prospect of a second final spot in three Premier League nights.
Rob Cross (#6) 3-6 Peter Wright (#8)
Peter Wright, who is at the stiff bottom of the Premier League with 2 points, opened the match almost uncharacteristically with a 12-darter to claim the first lead of the match.
Cross replied with a hit first arrow on the double, bringing the score to 1-1 by the Englishman. A narrowly missed arrow on the double bull prevented Wright from a huge 170 finish, but a (somewhat difficult) finish on D10 gave the Scot the lead back.
Wright happily steamed ahead with two league wins in a row with finishes from 89 and 40, after which the Scot pulled the match closer and closer to his goal and started to get the prospect of his second win in this Premier League season.
With the score at 1-4, Cross picked up another leg but then saw Wright one leg away from victory. One break proved enough for Wright, who finished the match expertly and ended with a 3-6 victory.
