Stuart Meaker took three wickets in nine balls to tear through Yorkshire and send Surrey to the Royal London One-Day Cup final for the second year running.
Steven Davies' century and 90 from Ben Foakes left the hosts chasing 256 at Headingley, and although they recovered well after Meaker's intervention thanks to a brave 68 from Tim Bresnan, they were bowled out 236 to lose by 19 runs.
Surrey now have the chance to avenge last season's Lord's defeat by Gloucestershire but for Yorkshire it was the second consecutive year that they have stumbled at the last-four stage and the 17th List A semi-final of 20 they have lost since 1979.
Yorkshire lost Adam Lyth to Jade Dernbach in the third over and skipper Alex Lees was bowled for 26 playing an expansive shot to opposite number Gareth Batty.
At 74 for two Yorkshire were still handily placed until Meaker began his lethal burst.
Jonny Bairstow drove to Dominic Sibley at midwicket, Gary Ballance was caught behind and Jack Leaning dragged on.
The slide to 81 for five was halted by Bresnan and 20-year-old all-rounder Matthew Waite, who enjoyed a fine match with three wickets and 38 runs in a stand of 80 in 16 overs.
Waite fell to Sam Curran when a leading edge picked out Batty at mid-on but Bresnan and Will Rhodes kept home hopes alive with a stand of 46 before Rhodes hesitated over a single and was beaten by Tom Curran's direct hit.
Tom Curran sent back both Azeem Rafiq and Steven Patterson and the match ended when Bresnan drove Dernbach to Sibley at long-off.
Earlier Surrey had found themselves eight for two but the early setbacks did not unsettle Davies, whose 104 followed consecutive Championship scores of 117, 52 and 56 against Yorkshire this season.
Jack Brooks struck in the day's second over as Sibley shaped to play to leg but missed and was given lbw.
Kumar Sangakkara was quick of the mark, cutting Bresnan for four, but in the same over the Sri Lankan drove loosely to Rafiq in the covers.
Left-hander Davies took boundaries off consecutive balls from Brooks as he hit 34 of the first 48 runs scored.
Waite's first delivery was flicked casually to long-leg by Rory Burns where Patterson held a good catch.
Three balls later Davies, on 43, drove back to the bowler but Waite spilled a difficult return chance and made the most of his life as he and Foakes' partnership of 130 clawed the visitors to a respectable total.
Rafiq was driven for six by Davies while Foakes moved smartly to his fifty from 51 balls.
Davies reached his century off 112 balls but four runs later he hit a low full toss from Waite straight to Rhodes on the midwicket boundary.
Surrey lost much of their momentum late on, Sam Curran going for 16 when he was bowled by Waite, who finished with three for 48.
Foakes struck Bresnan high over long-on for six but was denied a century when a ramp shot went wrong and he was caught by Brooks and d ebutant Ollie Pope was run out for 20 off the last ball of the innings.
Source: PA
