The 36-year-old, who oversaw proceedings for United at Snapdragon Stadium - with Erik ten Hag also in the dugout - chose a youthful side to face the Red Dragons.
Goals from Elliot Lee, Aaron Hayden and Sam Dalby saw Wrexham prevail in San Diego, with Marc Jurado netting the Reds only goal of the game just before the interval.
Speaking to MUTV post-match, Binnion was keen to emphasise that there are plenty of lessons to learn from his side's battling display overall.
''It was an eventful night, wasn't it? Obviously a couple of key decisions didn't really go our way, but we didn't play well enough,'' he began speaking to the MUTV cameras.