It's easy to understand why some Mamelodi Sundowns fans have started early celebrations after Saturday's emphatic CAF Champions League final first leg win over Zamalek.

The 3-0 win at an impressively packed Lucas Moripe Stadium in Atteridgeville makes Sunday's second leg in Alexandria seem like a mere formality, with Zamalek requiring to subject Sundowns to their biggest defeat in this campaign if they are to stand a chance of stopping Pitso Mosimane's team.

It will truly take some pathetic performance for Sundowns to become the first team in decades to lose the final with such a healthy first leg lead.

History shows that not since 2009 has a team lost a final after winning the first leg, and even then the margin was close enough to enable a comeback.

Seven years ago, DR Congo's TP Mazembe overturned a 1-2 deficit against Nigeria's Heartland, beating them 1-0 in the second leg to win on the away-goal rule after a 2-2 aggregate scoreline.

Another Nigerian side, Enyimba, also stunned Etoile Sahel in 2004 after losing 2-1 to the Tunisians in the first leg, only to beat them via the same scoreline in the return leg and clinch the title on penalties.

Zamalek themselves have previously reversed a poor result in the first leg by showing up in the second tie. In the 1996 final, they lost 2-1 to Shooting Stars of Nigeria, and then beat them by the same margin to send the match into penalties, which they won.

But Sunday's match is a bit different.

To start with, the margin - 3-0 - is so huge that perhaps Zamalek may require tons of good fortune, and refereeing assistance, to overcome Sundowns.

You would have to go back 40 years to the last time a team lost the final after having taken a 3-0 lead into the second leg.

Guinea's Haifa FC got the shock of their lives when, in 1976, they beat Algerian side MC Alger 3-0 at home, only for the latter to beat them by the same margin and win on penalties in the return leg at home.

This is something Sundowns should guard against on Sunday. Two quick goals could easily bring Zamalek into the game, and this time the Egyptians will be assisted by their notoriously hostile supporters, who will be flashing those green lasers in the faces of Downs players at every turn.

Sundowns, however, will know that they'll never get such an opportunity to rewrite the history books as now.

A goal for Downs in Alexandria would leave Zamalek needing to score five times against the SA side, a hugely improbable task.

That they have beaten the White Knights in every one of their three meetings in this campaign should also stand the Brazilians in good stead.

No country has produced more CAF Champions League winners than Egypt - with 14 spread across Al-Ahly (8), Zamalek (5) and Ismaily (one). SA's had only one, with Orlando Pirates in 1995.

This shows how difficult it is to win this competition.

Sundowns had better not make a mess of it on Sunday, having come this far, and especially with such a healthy lead.

I'm certain they will complete the job. But I can only celebrate after that job is indeed complete.