Portsmouth delivered a devastating blow to Leeds' survival hopes while virtually sealing their own Premiership status with a victory at Elland Road.
Aiyegbeni Yakubu went unchallenged to nod in a cross from Steve Stone in the ninth minute to put the visitors ahead.
The home side continued to push forward but Portsmouth took a two-goal cushion when Lomana LuaLua inched in a header.
Leeds grabbed a consolation goal when Ian Harte scored a penalty in the 82nd minute after a foul by Linvoy Primus.
Fighting for their Premiership survival, Leeds made a combative start to the match in front of a packed Elland Road.
Simon Johnson, stepping in for the suspended Mark Viduka, opened up a chance to make the pressure count after six minutes.
The 21-year-old found James Milner in space on the left but the midfielder opted not to shoot, instead flashing the ball back across the goal-mouth.
The home side's positive forward play was soon dampened by their own frailties in defence.
9 mins: Yakubu is in space and easily heads home
51 mins: LuaLua steals a header on the line for Portsmouth's second
82 mins: Harte slots home a penalty to grab a goal back
Amdy Faye threaded through a ball to Steve Stone who eluded Michael Duberry to race forward.
Yakubu was left unmarked and he gratefully nodded Stone's cross beyond Paul Robinson.
Portsmouth responded to Leeds' obvious panic by pouring forward and almost doubled their lead five minutes later.
But Arjan de Zeeuw fired the ball over the bar from six yards when he should have hit the target.
Leeds had not won a match this season after falling behind and again failed to convert several first-half chances to equalise.
Alan Smith, in fiery mood, headed beyond the post while Milner could not connect with Jermaine Pennant's dangerous cross across the face of the goal.
Things got worse for Leeds after the restart thanks to some more rash defending.
Duberry was saved the embarrassment of scoring an own-goal when his clearance inched past the post.
But Matthew Taylor's resulting corner found Yakubu whose goalbound header was spilled by Robinson and LuaLua pounced to head home on the line after 51 minutes.
Leeds seemed to lack a sense of urgency and their attacks spluttered out to the growing frustration of their fans.
Nerves were on show as substitute Nicky Barmby sent his chipped shot wide before Milner skied an effort from the edge of the 18-yard box.
But Eddie Gray's side were given a lifeline when the referee awarded a penalty after Primus pulled back Duberry in the box.
Leeds captain Harte sent Hislop the wrong way and a frantic 10 minutes followed as the home side went in search of the equaliser.
But Barmby and Stephen McPhail missed clear chances that would have gone some way to halting Leeds' slide back to Division One after 14 years of top-flight football.
Leeds: Robinson, Kelly, Caldwell, Duberry, Harte, Pennant,
Radebe (Lennon 71), Matteo (McPhail 45), Milner, Smith,
Simon Johnson (Barmby 59).
Subs Not Used: Carson, Kilgallon.
Booked: Caldwell, Kelly.
Portsmouth: Hislop, Primus, Stefanovic, De Zeeuw, Taylor,
Stone (Harper 80), Faye, Smertin, Quashie, Yakubu,
LuaLua (Sheringham 74).
Subs Not Used: Wapenaar, Curtis, Berkovic.
Booked: Smertin, De Zeeuw.
Referee: U Rennie (S Yorkshire).