Welshman Price averaged over 105 to make it back-to-back titles on the European Tour.
The four-time winner battled past Mike De Decker, Rob Cross and Dirk van Duijvenbode to set up a final showdown with Van Gerwen, who earlier beat Jose de Sousa, Peter Wright and Martin Schindler, dropping just five legs in the process.
The Iceman started the final in dominant fashion, taking out 134 to claim the opening leg before smashing in a 14-dart leg to quickly double his lead.
Van Gerwen hit back to take a leg of his own after Price missed four darts at double, but that did not stop Price from running riot with four straight legs to put himself 6-1 to the good and within two legs of victory.
The Dutchman replied with back-to-back legs as he threatened a comeback, but any hopes of a miracle were all-but ended when Price pinned tops for a 14-darter to move within a leg of the title.
Van Gerwen replied with another leg but the deficit was too much to recover as Price finally finished things off to claim his eighth Euro Tour title.
“I think I am half-German now!” joked Price, who has won four of the last five editions of the International Darts Open.
“I’ve been getting great support over the last couple of months and it is showing on the board. I know I’m playing well and I’m putting players under pressure.
“Michael wasn’t at his best today. He missed a couple of doubles and those crucial doubles have got to go in if you want to win tournaments.
“Thankfully I’ve been scoring well and those crucial doubles have been going in, because on another day it could have been a different story.
“I am sure it was a great game for the crowd. Michael is a great player and he will come back, so I’m happy to win this one.”
International Open results
Sunday April 2
Third Round
Afternoon Session (1300 local time, 1200 BST)
- Michael van Gerwen 6-1 Jose de Sousa
- Peter Wright 6-4 Alan Soutar
- Jonny Clayton 6-2 Dave Chisnall
- Martin Schindler 6-3 Nathan Aspinall
- Damon Heta 6-3 Niko Springer
- Dirk van Duijvenbode 6-5 Danny Noppert
- Rob Cross 6-3 Josh Rock
- Gerwyn Price 6-5 Mike De Decker
Evening Session (1900 local time, 1800 BST)
Quarter-Finals
- Michael van Gerwen 6-0 Peter Wright
- Martin Schindler 6-3 Jonny Clayton
- Dirk van Duijvenbode 6-4 Damon Heta
- Gerwyn Price 6-4 Rob Cross
Semi-Finals
- Michael van Gerwen 7-4 Martin Schindler
- Gerwyn Price 7-2 Dirk van Duijvenbode
Final
- Gerwyn Price 8-4 Michael van Gerwen
