- Championship Results / Championship Table
- League One Results / League One Table
- League Two Results / League Two Table
- Live Scores
Leeds centre-half O'Brien deflected Pompey substitute Nadir Ciftci's 93rd-minute cross into his own net for his second own goal of the afternoon to hand the visitors an unlikely point.
Simon Grayson's side extended their unbeaten run to 11 matches, but failed to capitalise on Cardiff's 4-1 defeat at Watford and closed out 2010 in fourth place in the table.
Max Gradel struck his fifth goal in four matches and skipper Jonny Howson slammed home his eighth of the season inside the opening 10 minutes to set Leeds on their way in front of a crowd of 31,556 at Elland Road.
But Portsmouth, who had beaten promotion-chasers Swansea and Norwich in their last two away games, hit back in the first half through David Nugent's superb strike.
Bradley Johnson gave Leeds another two-goal cushion in the 62nd minute, but Leeds defender O'Brien deflected Richard Hughes' shot beyond his goalkeeper Kasper Schmeichel for his first own goal within 60 seconds to reduce the deficit again.
Leeds had vociferous appeals for a late penalty turned down by Lancashire referee David Webb and were then denied three points three minutes into time added on when O'Brien again deflected into his own net.
Leeds had raced into a two-goal lead. Right-back Paul Connolly fired a fine ball across the six-yard box in the seventh minute and Gradel steered a right-footed finish into the bottom corner.
Within three minutes Leeds doubled their lead. Ross McCormack, making only his second start since arriving at Elland Road from Cardiff in August, picked out Howson in the area with a pinpoint cross from the left wing and the home skipper drilled an emphatic finish beyond Pompey goalkeeper Jamie Ashdown.
But Pompey deservedly pulled a goal back in the 33rd minute when Nugent finished brilliantly following Richard Hughes' cross into the area from the right.
Leeds stepped up a gear at the start of the second half. Snodgrass's blistering angled shot was superbly tipped away by Ashdown and while neither side created a goalscoring chance for the next 15 minutes, the game burst into life again just after the hour.
Ashdown pushed Gradel's header away for a corner and when the ball was swung in by Snodgrass, Pompey failed to clear and Johnson drilled the ball into the bottom corner from inside the area.
But Portsmouth hit back again to trail by just one goal within 60 seconds. Substitute Nwankwo Kanu made the opening for Hughes and the Pompey midfielder's shot was deflected in off O'Brien to make the score 3-2.
Leeds substitute Luciano Becchio then had a header turned away at full stretch by Ashdown and Snodgrass's 20-yard effort whistled narrowly over the crossbar.
Referee David Webb waved away Leeds' appeals for a penalty in the 78th minute when Pompey substitute Ibrahima Sonko barged into Snodgrass.
Snodgrass wasted a gilt-edged chance to seal it when dragging a shot wide from inside the area and Schmeichel denied Hughes with a fine save in the 87th minute, but the visitors snatched a point when O'Brien turned Ciftci's cross beyond Schmeichel in the 93rd minute.