After being sent in to bat, Zalmi piled up a stunning 246 for 3, before bowling Karachi out for just 87 in 16.1 overs in a complete one-sided demolition.
Zalmi suffered the worst possible start when Mohammad Haris fell for a duck in the opening over, but from there it was all about a brutal counterattack led by Babar Azam and Kusal Mendis.
Babar anchored the innings superbly with an unbeaten 87 off 51 balls, striking 10 fours and 2 sixes, while Mendis played the more explosive hand, smashing a breathtaking 109 off 52 deliveries with 14 boundaries and 4 sixes.
The pair added a match-defining stand that completely took the game away from Karachi, whose bowlers had no answer once the two settled in.
After Mendis fell in the 17th over, Michael Bracewell chipped in with a quick 6, before Abdul Samad provided the late fireworks with an unbeaten 40 off just 12 balls, blasting 4 sixes at a strike rate of over 333.
That final flourish lifted Zalmi to a towering 246/3, one of the biggest totals of the tournament.
In reply, Karachi’s chase never got going. They were blown away almost immediately as Muhammad Waseem, David Warner, and Salman Agha all fell inside the first three overs, leaving the Kings in deep trouble at 8 for 3.
Bangladeshi left-arm seamer Shoriful Islam made an instant impact by dismissing Warner with a sharp rising delivery, while Nahid Rana then tore through the middle order with serious pace.
Nahid finished with a sensational 3 for 7 in 4 overs, including the key wickets of Saad Baig, Khushdil Shah, and Adam Zampa, and looked genuinely hostile throughout his spell.
Teen spinner Sufiyan Muqeem also impressed with 3 for 18, while Iftikhar Ahmed chipped in with 3 for 9 to complete Karachi’s humiliation.
Only Azam Khan offered some resistance with 25, but Karachi never recovered from their early collapse and were eventually bowled out for just 87.