The Republic of Ireland youth international made his debut at Celtic Park and impressed his manager with his performance against the Staggies
Cork native O'Connell, who is a cousin of Munster and Ireland rugby player Paul O'Connell, played 73 minutes before being replaced by Israel international Beram Kayal and Lennon believes that the 18-year-old can be "pleased" with his display.
"Eoghan got better and better as the game went on," Lennon told the club's official website. "And the only reason we took him off was to give Beram a run out for the last half hour or so. But Eoghan can be really pleased with his performance."
Lennon conceded that the game, overall, was "flat" due to a lack of "edge", with the Bhoys having wrapped up the title against Partick Thistle last week, but is confident that his players will pick up the intensity next week.
"It was flat, maybe understandably so as there was no edge to the game, and the game itself in essence was probably far more important to Ross County than it was to us," said Lennon.
“I felt in the final third we were a little laboured but I understand that. The players have had little or no preparation for the game but I am sure we will be revitalised going into next week.
“They will get their trophy in one of the home games which will be an even greater celebration. At the minute we are digesting it all, as we have won it so early, which is down to the fantastic consistency shown by the players."