Northern Ireland striker Warren Feeney scored his fourth goal of the season to dent caretaker Brighton boss Bob Booker's hopes of landing the Withdean Stadium post on a permanent basis.
Feeney struck after 14 minutes and was then stretchered off with a suspected broken jaw as leaders Brighton slumped to their first league defeat since Booker took temporary charge earlier this month.
Northern Ireland international Feeney sidefooted Bournemouth in front after James Hayter's shot had been charged down by Brighton defender Adam Hinshelwood.
Feeney was then carried off on a stretcher 13 minutes before half time after Kerry Mayo's left-foot clearance had struck the ex-Leeds star in the face.
Bournemouth's manager Sean O'Driscoll afterwards admitted that Feeney could face a lengthy lay-off, furthering depleting the Cherries' paper-thin squad.
O'Driscoll said: "Warren was taken to hospital and he has a problem with his jaw, that is our main concern" "I won't know how serious the damage is until we get the results of the scan, but having one of your players put on a spinal board is always worrying.
"We lost Derek Holmes on Tuesday night and if Warren's injury is serious then we will have lost two strikers in two matches." Brighton showed little of the form which has catapulted them to the top of Division Two.
Bournemouth's margin of victory could have been more if captain Carl Fletcher's had netted with a header which rebounded off the post on the stroke of half time.
Booker, who is on a five-strong shortlist to succeed Reading-bound Steve Coppell said: "We are disappointed at the result, but the players have to bounce back.
"Football is easy when you are doing well, but it is how you respond when you lose that counts.
"We've got a big match at Brentford on Tuesday and we have to start another run of victories there."