Sidekick Ryan Reynolds was absent but McElhenney was joined in San Diego for the 19:30 local time kick-off by It's Always Sunny in Philadelphia co-stars, in wife Kaitlin Olson and Glenn Howerton.
The Hollywood celebrities were there as Phil Parkinson's League Two men saw off an Under-21s' Reds XI, although the latter performed admirably particularly when taking into account Dan Gore's red card early in the second half.
It was a first outing for our 2023/24 adidas away kit and McElhenney himself seemed to like it, judging by his pre-match comments to MUTV during a pitchside interview.