Division Three Southend thrashed QPR in a shock result that took them into the LDV Vans Trophy Southern Area final.
Drewe Broughton scored twice and Leon Constantine and Steve Clark also netted to take the Shrimpers a step closer to the Millennium Stadium.
Division Two title chasers Rangers were outplayed after Constantine gathered Mark Gower's early cross and fired Southend in front from close range.
QPR threatened when Clarke Carlisle had a header saved by Darryl Flahavan and then through Martin Rowlands.
And Carlisle missed a great chance to equalise in the 62nd minute when he headed Dean Marney's right-wing cross wide of the target from eight yards out.
It was to prove a costly miss as Southend went further ahead six minutes later on the counter attack.
Clark raced clear of Marc Bircham and steered the ball past keeper Chris Day and into the corner of the net.
Rangers seemed to give up after that and when they failed to clear Clark's cross, Broughton scored at the far post.
Broughton has his critics at Roots Hall, but his goal galvanised him and he was unlucky not to score again when he pounced on an error by Daniel Shittu and let fly with a shot that Day did well to tip away.
But from the resulting corner, Day failed to hold Leon Cort's header and Broughton had the simple task of tapping in his second goal and Southend's fourth.
Rangers' evening was summed up in injury time when substitute Steve Palmer headed the ball into the box and R's striker Paul Furlong blazed over from the edge of the six-yard box.
By then most of the 2,000 Rangers fans that made the trip to Essex had already seen enough and left the ground.