Vitoria held a 2-0 aggregate lead from their semi-final home leg clash and lost 3-1 away on Tuesday evening to advance to the next round on the away-goals rule, with the aggregate score at 3-3.
Zungu came on in the 54th minute with his side 2-0 down, with the clash looking to be heading for penalties, but 10 minutes later it was 3-0 as the hosts scored to give them an advantage.
However, Vitoria pulled one back to make it 3-1 within two minutes, and desperately needed to hold on to advance.
There was drama late on as Chaves won a penalty in referee's optional time, but 'The Conquerors' goalkeeper pulled off a save to keep the score at 3-1, which ensured their advancement to a seventh Portuguese Cup final, and their first since 2013.
The former Mamelodi Sundowns midfielder will now be contesting his first cup final abroad with the hopes of turning it into his first medal come May 28.