Luke Littler had his Premier League record of a seventh nightly win snatched away from him after a dominating display by Luke Humphries.
Cool Hand Luke won night 15 and qualified for finals night at the O2 Arena after beating Gerwyn Price 6-4 in the final.
Humphries let out a huge cheer alongside Price as the pair shared a hug on stage.
The top four for finals night have been confirmed as Littler, Jonny Clayton, Humphries and Price, which will take place on May 28.
Gian van Veen and Josh Rock got the night underway, with the Dutchman breaking the Northern Irishman in leg six, but was quickly answered back with a bullseye finish by Rock.
Van Veen then broke back after a mistake by Rock, winning the quarter-final with a smooth D16 finish.
Price and Michael van Gerwen then played out their crucial quarter-final for a spot in the top four.
The Welshman was throwing well, breaking the Dutchman's throw and not even giving him a sniff at a double on leg four.
Luke Humphries defeated Luke Littler in the semi-finals
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Price got the match all wrapped in leg 10, winning 6-4 after three match darts. The Welshman let out a huge cheer as he advanced into the semi-finals.
Humphries then thumped Stephen Bunting 6-0, not giving The Bullet a chance as he saw himself eliminated from the Premier League of Darts.
Littler broke Clayton twice in the opening three legs during their quarter-final, with the world number one oozing with confidence.
In a dominating display, the world champion thumped the Welshman 6-0 in arguably his best display in the Premier League so far.
Gerwyn Price also qualified for finals night
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Into the semi-finals and it was a must-win game for Van Veen against Price to try to jump up into the top four.
The Dutchman could not find a way to break the Welshman, who produced a brilliant display to win 6-4 and reach the final.
The victory meant that Price qualified for finals night in London.
Littler and Humphries were next up, with the teenage sensation picking up where he left off against Clayton.
Humphries win over Price means he qualified for finals night
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A memorable D18, D16 finish to win leg three brought a smirk out of Humphries in recognition of his counterpart's talent.
However, the world number one's hot streak would come to an end, having his throw broken three times as Cool Hand Luke won six legs in a row.
Humphries won the contest 6-3, setting up a final against Price, beating the Welshman 6-4 and qualifying for finals night.
Van Gerwen, Van Veen, Bunting and Rock are all out to produce a full British final in two weeks' time.
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