The Dutch defender ran half the length of the pitch through the St Johnstone defence before shooting past Alan Mannus. That delivered Celtic's 17th league fixture without defeat this season and maintained their prospect of going the entire 38-game campaign without loss.
"It was an unbelievable piece of individual brilliance," said Lennon of his £2.5m summer signing. "He has exceptional feet, he's a great defender. He certainly lit up the game here. He's had a big part to play in our clean sheet record and I think [with this sort of performance] we would have dropped points here last year.
"I thought we controlled the game on a difficult pitch. But we have to put teams away. At 1-0 you give teams encouragement."
The goal was van Dijk's third of the season, after he scored twice against Ross County in November. "In other games I have tried it and been tackled, but this time there wasn't a tackle," he said. "I think it was a good goal. Was it the best goal of my career? Yes, I think so. But I've not scored a lot so that's not difficult! It is an extra weapon for our team. Me and Efe [Ambrose] can do it."
Earlier this month, van Dijk said Celtic could complete the league season unbeaten, a view he repeated yesterday: "I think our belief is growing. We have enough quality to do it, we have a great team and the team spirit is also very good so it is possible. But we have to go out and do it."
Celtic were last night linked with the South Korean internationalist Han Kook-Young. The 23-year-old defensive midfielder plays for Shonan Bellmare in Japan's second division.
He said: "I have spoken to Celtic in Scotland, Augsburg, Freiburg and St Pauli in Germany, as well as clubs from China and the Middle East. I am hoping my future will be sorted soon," he added.
Meanwhile, Tommy Wright, the St Johnstone manager, felt his side should have had a penalty for a challenge by van Dijk on Stevie May. "I thought it was a penalty at the time," he said. "I've seen it since and nothing has changed my mind.
"I think we deserved to take something. Celtic created more chances but we contributed to a good game. I felt we deserved a goal. I'm pleased at the way we came back from losing a bad goal."