After leading in round one of the ZOZO Championship, Morikawa, 26, had to battle the elements in the second round, dropping back down the leaderboard.
However, the Japanese winds didn't deter the two-time major champion, and he bounced back in the third and fourth rounds, shooting back-to-back rounds in the 60s at the weekend, with a scintillating 7-under 63 in the final round to finish with a commanding six-shot lead over fellow American's Eric Cole and Beau Hossler.
Morikawa got his final round off to a blistering start with four birdies on the front nine before stamping his authority on the day by picking up two additional shots on the 12th and 15th, followed by finishing the round in style by holing a birdie putt on the 18th to seal the victory.
In typical Morikawa form, his TaylorMade irons and MG4 wedges proved to be the difference maker. He found 73.6% of greens in regulation throughout the week despite only managing to find the fairway with 36.5 of his tee shots.
Coming only weeks after he missed out on a spot in Luke Donald's Ryder Cup team, Meronk, 30, produced a stunning final-round comeback to secure a dramatic one-shot victory over Germany's Matthias Schmid.
Meronk shot back-to-back 6-under 66s on both Saturday and Sunday to chase down the leaders.
Things were looking bleak for Meronk early in his final round, as he saw himself drop two shots in the first three holes. However, he rallied well to finish the back nine with two eagles on the 6th and 9th to bring him back into contention.
He then made four birdies on the back nine to eventually overtake Schmid after the German stuttered with a bogey on the 16th, handing the lead to Meronk.
Collin Morikawa WITB 2023
Driver: TaylorMade SIM (8 degrees; Mitsubishi Diamana D+ Limited 60 TX)
3-wood: TaylorMade SIM (14 degrees; Mitsubishi Diamana D+ Limited 80 TX)
5-wood: TaylorMade Stealth 2 (18 degrees; Mitsubishi Diamana D+ Limited 80 TX
Irons: TaylorMade P770 (4), P7MC (5-6), P7CM (7-PW) True Temper Dynamic Gold Tour Issue X100
Wedges: TaylorMade MG4 (50-09SB, 56-08LB), TaylorMade MG4 TW (60) True Temper Dynamic Gold Tour Issue S400
Putter: TaylorMade TP Soto
Ball: TaylorMade TP5x
Adrian Meronk WITB 2023
Driver: PING G430 Max (10.5 degrees; Fujikura Speeder Evolution V1 661-X)
3-Wood: PING G425 Max (14.5 degrees)
3-Hybrid: PING G425 (19 degrees)
Irons: PING iBlade (3-PW)
Wedges: Titleist Vokey SM9 (50, 54, 58)
Putter: PING Vault 2.0 Ketsch
Ball: Titleist ProV1x