Partridge led for 63 of the 75 laps and had a best speed of 98.999 mph and a best lap time of 18.152 second at the ½-mile oval short track. His overall time was 32:25.7 seconds.
Partridge led until a restart on lap 62 and fell behind second place finisher Alex Haase of Las Vegas.
Partridge and Haase nearly crashed moments later with Partridge regaining the lead for good on lap 64.
Partridge was very excited about the win.
"That was so much fun," Partridge said. "Irwindale is the best short track in the nation. To be able to finish so well, it's amazing. It feels like we've earned it. There were a ton of people on board. This is the race of races as far as we're concerned on the west coast over here."
Haase had a best speed of 98.517 mph, best lap time of 18.271 seconds and overall time of 32:56.5 seconds.
Finishing third was Tustin's Andy Allen. He had a top speed of 99.059 mph, best lap time of 18.171 seconds and an overall time of 32:26.9.
Partridge is sponsored by Eshleman Racing in Fontana.
A BEAUTIFUL WEEKEND OF NASCAR RACING was capped Saturday night with the Late Model 50. Finishing first was Sean Woodside of Saugus who never trailed in a race marred by several crashes and lots of yellow flags.
Red flags were also waved on laps 22 and 46 due to bad crashes. In addition, the caution flag was waved with two laps to go.
Woodside had a best lap time of 18.852 and top speed of 95.648. He was 0.281 off the pace.