Wrexham, Manchester United Field Invader Blasted By Security ... After Wild Run On Pitch

A field invader during the Wrexham vs. Manchester United game found out very quickly he should've just stayed in his seat ... because moments after he stormed the pitch -- he was decked by security.

The man's wild run during the much-anticipated exhibition soccer game all went down on Tuesday night in San Diego at Snapdragon Stadium.

In the second half of the tilt ... the fan, for some reason, hopped over a stadium wall, stripped off his shirt -- and took a joyride through the players on the field.

Video shot from fans inside the venue shows the man was able to avoid guards for a while ... but once they caught up to him, they plowed him into the turf.

Somehow -- despite the brutal blow -- the guy was able to get up ... though he was eventually led off the field in cuffs.

Despite the bizarre scene ... Wrexham -- playing in America for the first time ever -- was able to cruise to a big, 3-1 win -- much to team owner Rob McElhenney's delight!