Isaacs was also a member of the Celtic team that eliminated an on-form Pirates side in the 2012 Telkom Knockout quarterfinals before going on to beat a star-studded Mamelodi Sundowns to etch their names into the 'underdog' history books of South African football.
This week, Siwelele coach John Maduka openly admitted that they are once again the 'underdogs' in Saturday's final against Pirates at Moses Mabhida Stadium.
The ex-Amakhosi centre-back, who has experience of beating the Buccaneers, says the Free State-based outfit need to try and contain their opponents at least for the first 45 minutes if they are to stand any chance of being crowned the 2020 MTN8 champions.
"They've been in a final as recently as last season's Nedbank Cup, which they lost against Sundowns, and they are basically the same players, so I'm sure they've learned from their mistakes," Isaacs tells snl24.com/kickoff.
"They are playing a Pirates side that are also highly motivated, so as much as they want to play, they must watch out for Pirates.
"Pirates is also very, very dangerous in counter-attacks, they've got speed and their striker [Zakhele] Lepasa is on form. You know how Pirates play the first 20 - 30 minutes, they come out guns blazing.
"If they can just contain Pirates in the first half – the longer the game stays 0-0, the better for them because that's how we [Celtic] won against Sundowns [in 2012]."
Asked to compare the current Celtic teams and the one from 2012 Isaac's said: "We had a good team, a balanced team, and there was no stress, we were working with a good mixture of experience and youngsters, and also we had a very, very good coach in Clinton Larsen.
"I like this current team as well; they are playing without fear you. They are not scared to attack, and they are keeping it tight at the back as well.
"The goalkeeping department is also fantastic. Celtic are one of my favourite teams that I like watching. Not only now, for the last two, three years.
"They play without fear and that is nice to watch but they must watch out for Pirates – they haven't won any silverware in a very, very long time."