Rendell fired Luton to the biggest shock of the fourth round last month when he scored the winner for the conference side against Barclays Premier League outfit Norwich at Carrow Road.
Victory for Luton will make them the first non-league team to reach the quarter-final of the world's most famous cup competition in 99 years.
Rendell did his best to insist Luton were not thinking past the game, but he could not help but let his mind wander when asked about the prospect of a potential quarter-final meeting with Manchester United, the team who the striker has supported all his life.
"I am a United fan so I'd love to play them in the next round," Rendell said.
"If we do get past Millwall then I will be sitting on the edge of my seat to see if we draw United. My favourite memory of the FA Cup growing up was watching that Ryan Giggs semi-final goal against Arsenal. It was just a fantastic moment and it just gave me hope as a kid to emulate him and do something similar."
There is no reason to suggest that should Luton, finalists in 1959, can not reach a Wembley semi-final if they beat an out-of-sorts Millwall and get a favourable draw in the last eight.
After all, shocks have become the norm in domestic cup competitions this year. Norwich, Liverpool, Aston Villa and Tottenham have all bowed out of the FA Cup to lower league opposition, but the biggest giant-killings have come in the Capital One Cup courtesy of npower League Two side Bradford.
Rendell admits the Yorkshire club's exploits in the League Cup, where they knocked out Arsenal and Aston Villa, mean the game against a team sitting 67 places below them in the league suddenly becomes less daunting.
"They are an inspiration to us," the 26-year-old added.
"Look at the teams they have beaten. They went and beat Aston Villa over two legs. It proves that it can be done.
"It showed you can beat anyone on your day like we did against Norwich. "We weren't massively outclassed against Norwich so the boys have nothing to fear against Millwall.
"There is definitely a feeling in the squad that we can pull off another shock. We have beaten Wolves at home, we beat Norwich away so why can't we beat Millwall here?"
Rendell admits his life has changed since he stabbed the ball past Declan Rudd to give the Hatters their famous win in Norfolk three weeks ago.
The grounded striker is reluctant to hog the limelight, however, preferring instead to lavish praise on manager Paul Buckle, whose position has come in to question in recent weeks after his team slipped to seventh in the Blue Square Bet Premier.
The striker says Buckle, who had previous spells as manager of Torquay and Bristol Rovers, has made him feel like he belongs at Luton following a nomadic eight-and-a-half year career that has seen him play for a staggering 14 clubs.
"If you don't win a game here you are going get questioned, everyone knows that," Rendell said.
"But he has been great, the boys obviously understand where he is coming from. I think he is taking us in the right direction. The results in the league haven't been anywhere near good enough in the league recently, but hopefully that's a blip. "It definitely feels like home here for me now."
Bedfordshire Police warned fans without tickets not to travel to the game.
The authorities are keen to avoid a re-run of the rioting which erupted following the last meetings between the two clubs in 1985 when 47 people were injured, 33 of them policemen.