Lui scored the opening try in a 36-12 win over Hull KR which sealed fifth place in Betfred Super League and booked an elimination play-off at Wigan Warriors next Thursday.
“Rob was excellent,” Agar said of Lui, who will retire at the end of this season.
“Kruise Leeming was excellent and I thought we had a lot of performances across the board.
“Tom Briscoe played centre and then did 30 minutes in the second-row, he was great; Luke Briscoe was really good on the wing and Ash Handley had a good game. James Donaldson and Tommy Holroyd in particular came off the bench and played very well.”
Rhinos were assured of a place in the play-offs before kick-off and Agar hailed a “really pleasing” performance.
He added: “Coming into the game it was a bit funny, preparing all week for a must win game and then finding out it wasn’t.
“I thought we prepared really well and what we wanted to execute we did, a lot.
“For big chunks of the game I thought what Hull KR have been good at all season, we handled really well.
“I thought we unpicked them really well offensively in the first half.”