Middlesbrough's hopes of avoiding relegation suffered a major setback as they lost heavily at Bournemouth after playing for 70 minutes with 10 men.
Midfielder Gaston Ramirez was sent off for two bookable offences after 20 minutes - one for diving and another for a reckless challenge on Marc Pugh.
They were already trailing 2-0 - Joshua King scoring from close range after 96 seconds, before Benik Afobe's finish.
Marc Pugh's curling effort made it 3-0 and Charlie Daniels added the fourth.
Boro, 19th in the Premier League table, are nine points from safety with just five games remaining.