With Chelsea leading their preseason friendly against Portsmouth 1-0 thanks to a horrible/perfect header for an own goal from Tal Ben Haim (who did more in that moment for Chelsea than in his entire time with the club), John Terry decided to introduce his boot to Luke Varney face late in the match.
Terry kept his boot face-high after an attempt to clear the ball from his own box and caught Varney square in the kisser with his studs. Though Varney would be OK, it probably wasn't a fun experience for him. Still, it was nowhere near as bad as the time Terry himself got kicked in the face and nearly swallowed his own tongue...
Four years later and that's still awful to watch.