The Greece forward netted twice in as many minutes after Kris Commons had fired the champions ahead, and Samaras made sure of the Scottish Premiership points at Rugby Park on Saturday with a header on 87 minutes.
"I thought he was world-class today," Lennon said. "You can talk about the standard of SPFL football or this and that but when you see a player play as well as that, no matter the standard, you can tell that he is a top-class player.
"I thought he was brilliant. Everything about his game was of the highest quality. I am delighted he got the goals but even if he hadn't got the goals, I thought his all-round play was magnificent."
But Samaras played down the significance of his first hat-trick in three years and insisted it would mean nothing if Celtic failed to defend their league title.
"It is just goals, just three points," he said. "It is not a really important thing.
"The important thing is at the end of the season to win the trophy. If we don't win the trophy what is the point of scoring a hat-trick against Kilmarnock?"
Goals from Sammy Clingan and Sean Clohessy had hauled Kilmarnock back into the game at the break, and boss Allan Johnston was encouraged by his side's fighting spirit.
But the Killie boss also insisted the defeat had nothing to do with the background bickering at Rugby Park, where several home fans protested against chairman Michael Johnston's decision to sell cut-price tickets for the game to Celtic fans.
"We have just got to concentrate on the football," said the Killie manager.
"It is easy enough to make excuses and say that makes a difference but it is the football we have to concentrate on and it shouldn't affect the players.
"It is amazing to think we got beat 5-2 there. It was a really good performance but we lost cheap goals."