Second division Brighton were well beaten as they crashed out of the FA Cup at Lincoln.
Albion never recovered after going behind to a 13th minute penalty and in the end Lincoln could have won by and even greater margin.
Lincoln went in front when Brighton defender Guy Butters pulled the shirt of Lincoln's Ben Futcher inside the box.
Referee Nigel Miller immediately answered a spot kick which Paul Mayo hammered low into the net past the dive of keeper Michels Kuipers.
Lincoln opened up Brighton again two minutes later when a corner from Mayo was flicked across goal by Ricky Butcher but Gary Fletcher was just unable to get the touch needed to put the ball into the net.
Lincoln had more success eight minutes before half time thanks to the persistence of Francis Green.
The striker forced his way down the left before firing over a cross which was converted by Matthew Bloomer.
Brighton's Chris McPhee was denied by a diving save from Allan Marriott and second's later the Lincoln keeper did well to keep out a powerful shot from Richard Carpenter.
Brighton's misery increased in the 59th minute when Kuipers dropped a corner at the feet of Simon Yeo and the striker made no mistake from 10 yards.
Leon Knight tried to hit back but after turning two defenders he saw his shot held by Marriot.
But Brighton snatched a consolation goal in the 83rd minute when Chris McPhee headed home across from substitute John Piercy.
Piercy then flashed a late shot narrowly wide but it was too little too late for Brighton.
Brighton manager Mark Mcghee said after: "Its always disappointing to lose. I'm not pleased. I hope the players will feel embarrassed by their performance.
"We should be able to come to somewhere like this and win." Lincoln manager Keith Alexander said: "We were on top from start to finish. I thought we could have got more goals.
"The players have gelled together well and we've been playing some good football in the last six or seven weeks."