They usurped Hull KR from fifth spot last night with an impressive 36-12 win over the Robins at Emerald Headingley.
It means they head to fourth-placed Wigan next Thursday in a sudden-death eliminator.
Leeds won 14-0 there just last month which will give them confidence.
Agar insisted: “We did play them about three weeks ago. But I think it will be a totally different style of game, especially to tonight.
“We’ll have to think about team selection. We’ve got some guys coming back but – at Wigan, in the play-offs, this time of year –it will be tough. Defensively they really aim up and it’s a play-off game. We expect a real tight contest but we’ve all to play for.”
Rhinos were assured of a place in the play-offs before kick-off after Castleford Tigers lost against Warrington Wolves on Thursday.
Agar said: “Coming into the game it was a bit funny, preparing all week for a must-win game and then finding out it wasn’t.
“For big chunks of the game I thought what KR have been good at all season, we handled really well. We unpicked them really well offensively in the first half.”
Rovers were 24-6 down at half-time and finish sixth so head to Warrington on Friday but they lost hooker Matt Parcell (torn pectoral) and prop Will Maher (hamstring) to injuries.
KR coach Tony Smith said: “We were unpicked in that first half.
“I thought the Rhinos were the better team. They found more energy and some good plays. They blew our legs off a little bit. We’ve done that to teams before.”
Report: Page 6.