Edcarlos scored two minutes from time to give Mineiro a dramatic 4-1 quarter-final second-leg win over Corinthians at the Estadio Governador Magalhaes Pinto on Wednesday.
The centre-back's goal in Belo Horizonte handed Mineiro a 4-3 aggregate victory, just as Corinthians were seemingly on track to progress on away goals.
Mineiro trailed 2-0 heading into Wednesday's return leg and the odds were firmly stacked against the hosts when Paolo Guerrero gave Corinthians a fifth-minute lead in Belo Horizonte.
Guerrero outmuscled his opponent before firing low and hard beyond Mineiro goalkeeper Victor.
Mineiro were offered a glimmer of hope in the 24th minute, when Luan glanced his header past Corinthians keeper Cassio.
And the home side found themselves well and truly back in the contest eight minutes later after Guilherme scored from outside the box, albeit with some help from a deflection.
Guilherme netted his second of the match with 15 minutes remaining, curling past Cassio as Mineiro moved level on aggregate, though Corinthians remained in the box seat on away goals.
But just as Corinthians fans started preparing for the semi-finals, Edcarlos popped up and headed home from a corner in the 88th minute.
Mineiro will now turn their attention to Flamengo, who also won through to the semis on Wednesday.
Gabriel's 64th-minute strike was all that separated Flamengo and second-tier America RN as the Brazilian Serie A side earned a semi-final showdown with Mineiro.
Both teams ended the match with 10 men following red cards to America's Lazaro and Flamengo's Marcelo.
Top-flight champions Cruzeiro survived an almighty scare to qualify for the final four.
Cruzeiro conceded three unanswered goals in the last 30 minutes to lose 3-2 at second-tier side ABC.
But the Brazilian high-flyers managed to progress on away goals after winning the opening leg 1-0 on home soil.
Missing a number of regulars - including Everton Ribeiro, Marcelo Moreno and Ricardo Goulart - Cruzeiro still took a two-goal lead into the break thanks to Henrique and Willian.
It was all one-way traffic in the second half, however, as ABC trio Rodrigo Silva, Xuxa and substitute Alvinho gave Cruzeiro a big fright.
David Braz scored twice as Santos routed Botafogo 5-0 on Thursday to book a clash with Cruzeiro.
Santos progressed 8-2 on aggregate.
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