The Canada-based fan was giving a running commentary on Twitter, describing the opening 45 minutes as "the worst half of football we've played all season and pre-season" adding: "The Callum McGregor Left Back Experiment sounds like the name of a 1970s prog rock band. And how I wish that was all it was."
Diamond also had a pop at the manager, questioning Lennon's team selection, saying: "McGregor had a shocker tonight. We all saw that game at Ibrox. Don’t know what Lennon was thinking of."
The 49-year-old also had a message for the Celtic skipper, who gave away a penalty with a crazy handball in the second half.
Diamond wrote: "I know he loves the club. I know he’s the fittest guy in the team. I know he lives rent free in opponents heads with hilarious results. I know his team mates adore him.
"I know the fans adore him. But Broony needs to be more than a meme."
Brown was also forced to publicly apologise after appearing to "like" a tweet criticising the Celtic team selection, insisting he "must have touched the button by accident".