Cardiff missed the chance to secure a place in the play-offs after Luciano Becchio's equaliser for Leeds.
The striker glanced home a header after Paul Connolly's determined chase saw him pull the ball back for Becchio.
Joe Mason had put Cardiff ahead when he collected a raking crossfield pass and lifted his shot over Andy Lonergan.
Lonergan went on to deny Kenny Miller and Andrew Taylor with top-class saves to keep Leeds in it, although they had Leigh Bromby carried off injured.
The defender appeared to catch his studs in the turf midway through the first half and crumpled in agony, receiving oxygen before medical staff called for a stretcher.
A victory for Cardiff would have seen the Bluebirds guarantee their place in the play-offs.
And nearest challengers Middlesbrough later beat high-flying Southampton 2-1, leaving Cardiff unable to start planning for post-regular season football.
Cardiff, unbeaten now in their last nine matches - albeit with six draws - now face a nerve-jangling last-day finale at Crystal Palace in their bid to make it a hat-trick of top-six finishes.
Bluebirds midfielder Liam Lawrence had an early effort saved by Leeds goalkeeper Lonergan, and at the other end Ross McCormack headed wide against his former club after good work from Robert Snodgrass.
Mason skewed his close-range effort off target as Cardiff sought an early breakthrough, but neither side created a further chance before Leeds defender Bromby was carried off in the 32nd minute.
Bromby, who appeared to slip awkwardly unopposed and required immediate medical attention, was replaced by Paul Connolly.
That setback appeared to distract the visitors and Cardiff caught them napping to take the lead four minutes before the break.
Mason, who this week signed a new four-year deal with Cardiff, raced on to Peter Whittingham's long pass from inside his own half and held his nerve to lob the ball over the advancing Lonergan from inside the penalty area.
City striker Miller was then denied in fine style by Lonergan, who kept out the Scot's angled 18-yard drive as Cardiff threatened to increase their lead in time added on at the end of the first half.
Leeds began the second half with renewed purpose. Thompson's fierce shot was blocked by Cardiff defender Ben Turner and Becchio headed wide from 12 yards soon after.
Leeds boss Neil Warnock sent on Ramon Nunez and Danny Webber for McCormack and Adam Clayton respectively just before the hour-mark and the visitors then went close when Danny Pugh's 20-yard effort flew wide.
The visitors continued to give as good as they got, but Lonergan was forced into another excellent save in the 70th minute when keeping out Taylor's goal-bound volley.
Leeds then dealt Cardiff's play-off hopes a blow with the equaliser three minutes later. Substitute Connolly swung over a fine cross from the right and Becchio rose above the home defence to head beyond Cardiff goalkeeper David Marshall into the bottom corner.
Cardiff substitute Filip Kiss fired wide from the edge of the area and Whittingham failed to keep his 87th-minute free-kick on target as Leeds held on for a deserved point.
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Live Text Commentary
Full Time The referee signals the end of the game.90:00 +4:07
Luciano Becchio handles the ball and concedes a free kick. Direct free kick taken by David Marshall.90:00 +1:41
David Marshall restarts play with the free kick.90:00 +1:41 Substitution
Substitution Darcy Blake is brought on as a substitute for Kevin McNaughton.90:00 +1:41
Free kick awarded for an unfair challenge on Kevin McNaughton by Ramon Nunez.90:00 +0:46 Substitution
Substitution (Cardiff) makes a substitution, with Robert Earnshaw coming on for Kenny Miller.86:35
Alex Bruce gives away a free kick for an unfair challenge on Joe Mason. Direct effort from the free kick comes in from Peter Whittingham.85:24
The official flags Alex Bruce offside. Free kick taken by David Marshall.84:35
Paul Robinson takes the direct free kick.84:35 Booking
Booking Booking for Aron Gunnarsson for unsporting behaviour.84:24
Free kick awarded for an unfair challenge on Luciano Becchio by Aron Gunnarsson.82:35
Free kick awarded for an unfair challenge on Alex Bruce by Joe Mason. Andy Lonergan takes the free kick.81:04
Effort from the edge of the area by Filip Kiss goes wide of the right-hand post.78:16
Free kick awarded for an unfair challenge on Paul Robinson by Kenny Miller. Direct free kick taken by Andy Lonergan.76:10
The official flags Aron Gunnarsson offside. Andy Lonergan restarts play with the free kick.75:36
Liam Lawrence takes a inswinging corner to the near post, Danny Pugh makes a clearance.74:21
Danny Pugh gives away a free kick for an unfair challenge on Liam Lawrence. Direct free kick taken by Ben Turner.72:21
Paul Connolly provided the assist for the goal.72:21 Goal scored
Goal! - Luciano Becchio - Cardiff 1 - 1 Leeds Luciano Becchio scores a headed goal from inside the six-yard box. Cardiff 1-1 Leeds.70:55
Ramon Nunez is adjudged to have handled the ball. Direct free kick taken by David Marshall.
Ramon Nunez fouled by Andrew Taylor, the ref awards a free kick. Free kick taken by Andy Lonergan.69:23
Foul by Liam Lawrence on Ramon Nunez, free kick awarded. Andy Lonergan takes the free kick.69:08
Effort from 12 yards by Andrew Taylor. Save made by Andy Lonergan.66:21
Danny Webber produces a left-footed shot from just outside the box that misses to the right of the target.66:06
Ramon Nunez has an effort at goal from 20 yards. Blocked by Peter Whittingham.63:54
Zac Thompson challenges Filip Kiss unfairly and gives away a free kick. Free kick taken by David Marshall.63:33
Corner taken left-footed by Robert Snodgrass from the right by-line, clearance made by Ben Turner.63:12 Substitution
Substitution Stephen McPhail leaves the field to be replaced by Filip Kiss.61:53
Shot from just outside the area by Danny Pugh misses to the left of the target.58:44 Substitution
Substitution Adam Clayton goes off and Ramon Nunez comes on.58:44 Substitution
Substitution (Leeds) makes a substitution, with Danny Webber coming on for Ross McCormack.57:58
The free kick is swung in right-footed by Liam Lawrence.57:58 Booking
Booking Booking for Adam Clayton for unsporting behaviour.57:41
Unfair challenge on Aron Gunnarsson by Adam Clayton results in a free kick.55:19
Peter Whittingham fouled by Paul Connolly, the ref awards a free kick. Peter Whittingham delivers the ball from the free kick left-footed from right channel.54:35
Mark Hudson produces a header from inside the area that goes over the crossbar.52:24
Free kick awarded for a foul by Alex Bruce on Liam Lawrence. Liam Lawrence takes the direct free kick.48:21
Stephen McPhail gives away a free kick for an unfair challenge on Ross McCormack. Ross McCormack takes the direct free kick.47:26
Headed effort from deep inside the penalty area by Luciano Becchio misses to the left of the goal.46:43
Shot by Zac Thompson. Blocked by Ben Turner.45:01
The referee gets the second half underway.45:00 +6:09 Half time
Half Time The match has reached half-time.45:00 +5:21
Liam Lawrence fouled by Danny Pugh, the ref awards a free kick. Mark Hudson takes the direct free kick.45:00 +2:45
Peter Whittingham produces a drilled right-footed shot from 20 yards. Blocked by Alex Bruce.45:00 +2:31
Kenny Miller has an effort at goal. Save by Andy Lonergan.45:00 +0:30
Shot from inside the area by Kenny Miller clears the bar.40:38
Assist on the goal came from Peter Whittingham.40:38 Goal scored
Goal! - Joe Mason - Cardiff 1 - 0 Leeds Goal scored by Joe Mason from close range to the bottom left corner of the goal. Cardiff 1-0 Leeds.35:41
Andrew Taylor concedes a free kick for a foul on Ross McCormack. Tom Lees takes the free kick.35:07
Short corner taken by Liam Lawrence from the left by-line.33:12
Paul Robinson handles the ball and concedes a free kick. Peter Whittingham takes the free kick.31:41 Substitution
Substitution Paul Connolly on for Leigh Bromby.26:02
Luciano Becchio challenges Kevin McNaughton unfairly and gives away a free kick. Direct free kick taken by David Marshall.15:20
The assistant referee signals for offside against Ross McCormack. Kevin McNaughton takes the free kick.13:35
Unfair challenge on Robert Snodgrass by Stephen McPhail results in a free kick. Free kick crossed left-footed by Robert Snodgrass, clearance made by Ben Turner.11:44
Liam Lawrence challenges Zac Thompson unfairly and gives away a free kick. The free kick is delivered right-footed by Ross McCormack from left wing, save made by David Marshall.10:36
Effort from inside the six-yard box by Joe Mason goes wide right of the goal.10:12
Corner taken short by Peter Whittingham.10:01
Shot by Kenny Miller from 18 yards. Blocked by Alex Bruce.5:02
Corner taken left-footed by Robert Snodgrass, Header from close range by Ross McCormack misses to the right of the goal.2:26
Handball decision goes against Ross McCormack. Aron Gunnarsson restarts play with the free kick.1:26
Joe Mason is caught offside. Andy Lonergan restarts play with the free kick.0:56
Liam Lawrence has an effort at goal from 20 yards. Comfortable save by Andy Lonergan.0:00
The ref blows the whistle to start the match.
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