Crystal Palace 1 Bristol City 2 (agg 2-4):Extra-time goals from Lee Trundle and Michael McIndoe sent Bristol City into the Coca-Cola Championship play-off final as they ended Crystal Palace's promotion hopes at Ashton Gate.
Ben Watson's first-half header had drawn Palace level on aggregate follow City's 2-1 win on Saturday, but the Eagles midfielder turned from hero to villain when he missed a penalty with 18 minutes remaining.
That forced extra time but Trundle's left-footed curling effort in the 104th minute and McIndoe's drilled free-kick five minutes later ensured Gary Johnson's side will face either Hull or Watford on May 24 for a place in the Barclays Premier League.
It was a first play-off semi-final defeat in six attempts for Palace boss Neil Warnock but he could have few complaints over City progressing.
The visitors had their lead and it was a moment to forget for Robins defender McCombe, who should have left Danny Butterfield's floated cross for goalkeeper Adrian Basso but instead gave the ball straight to Watson.
The match moved at a furious pace with City threatening down the wings and Palace responding on the counter.
But the pendulum appeared to swing firmly in Palace's favour when Nick Carle mistimed a challenge on Soares - only for Watson to fire his spot kick against the foot of the keeper's right-hand post, prompting the majority of Ashton Gate to erupt.
Inevitably, both sides began to run out of steam as the prospect of extra time loomed large, but each came within inches of snatching victory at the death.
Trundle came close with a delightful lob which clipped the top of the crossbar.
And the former Swansea striker then went one better with a minute of the first half of extra time remaining, curling a stunning effort beyond Speroni.
Adebola should have sealed it early on in the second period but the Robins made sure when Carle laid the ball off for McIndoe to fire a low shot inside the left post.
The result prompted a mass pitch invasion at the final whistle as Johnson's men moved within one game of ending their 28-year exile from the top flight.