Hampshire are through to their third consecutive Freidns Life t20 finals day after a breathtaking run-chase at Trent Bridge.
Nottinghamshire Outlaws posted a total of 178 for seven after being put in by the Royals in the last of the four quarter-finals.
But Neil McKenzie (79 not out) masterminded a superb chase which saw him help himself to three boundaries in the final over as he struck the winning runs off the last ball.
The Royals join Sussex, Somerset and Yorkshire in the final four.
Hampshire were beaten semi-finalists at Edgbaston last term after taking the crown on home turf in 2010.