According to the Football411 website, the Buccaneers bounced back from the goalless draw in their opening Group A clash against AC Leopards last month with a dominant display in Egypt this past weekend as they handed the seven-time continental champions their first home defeat in 23 CAF matches, winning the game 3-0.
Fish, who helped Pirates to the title in 1995, believes the Sea Robbers will now have a target on their back when they take on Zamalek, who will be well aware of the result they inflicted on their north African neighbours.
"It is obvious that the team has matured very well since their victory over TP Mazembe," Fish told the PSL club's official website.
"But having said that, they need to remain focussed - the players will have to play very smart now and understand that the going will get tougher.
"The next match against Zamalek won't be easy - those guys will be very well prepared for this match. The result against Al Ahly will make them prepare better than ever before.
"Pirates is the team to beat right now and they better be prepared for any backlash from the North African giants."
He added: "It is important to remain humble and approach the remaining matches with the same mentality - go there as underdogs, but make sure that if we get a chance to hurt the opposition, we do it."