Khulna looked out of the game at 117-5 after 15.2 overs, when Yasir came to the middle.
The right-hander then hit Naseem Shah for a six in the 17th over and a four off Mustafizur the next over to make the equation for the last over to 17 runs.
Comilla captain Imrul Kayes then took a brave call and gave the ball to off-spinner Mosaddek Hossain in place of Mukidul Islam, who had leaked 37 runs off two overs.
Mosaddek started with a dot and then conceded a single against Wahab Riaz.
Yasir then hit him for a couple of fours through the leg-side to bring the equation down to eight of two deliveries.
Yasir ran a couple of runs from the penultimate ball, leaving six runs for the final delivery.
Mosaddek was up to the task, as he fired in a fuller length delivery, which Yasir couldn’t get underneath.
Sent to bat, Comilla rode on Rizwan’s unbeaten 54 off 47 balls after Liton’s 50 off 42 deliveries to post a decent total.
Liton and Rizwan gave Comilla a steady start with a 65-run opening stand off 59 balls.
The partnership ended when Liton, after reaching his half-century in the previous delivery with a four from a reverse sweep, attempted a slog sweep off Nahid which went straight into the hands of Andrew Balbirnie.
Johnson Charles then gave the innings some much needed impetus with a brisk 39 off 22 balls, which included five sixes.
After Wahab dismissed Charles, it was Rizwan’s turn to take on the bowlers.
Rizwan, who was batting on 38 off 37 balls at one point, along with Khushdil Shah (13 not out off 11 balls) took 34 runs off the final three overs to take the total over 160.
With the win, Comilla remained third in the table with five wins in eight games. Khulna, on the other hand, are fifth in the seven-team table with two wins in seven matches.