Under new coach Tony McGahan, the Rebels are working to turn their biggest weakness into their greatest strength.
Last year they conceded 515 points, including 65 tries, to sit only above demoted South African side the Southern Kings.
The next worst Australian side was NSW, who conceded 371 points.
Ahead of their first pre-season clash with the Waratahs on Saturday in Albury, Rebels back Tom English said defence was a priority.
"We've moved in a new direction where we're a very defence-oriented team so we've been working hard on our contact and our breakdown so we're really looking forward to getting into it," he said.
"We want that to be our point of difference.
"We're going to hurt sides; we're looking to turn over ball and really make them earn points."
English said the Rebels needed to change their mind-set in defence as well as improve their technique.
"You've got to want to get dirty and help out your mate beside you but it's also a lot of technique so we've been doing a lot of drills focusing on the break-down, focusing on the tackling technique and really nailing down the detail there."
When their attack fired the Rebels managed to score some exciting tries last season and English said they still had a licence to thrill.
"There's still going to be some of that razzle-dazzle but we're going to earn that off the back of our hard work.
"We're not going to be throwing 50:50s, we're going to be working for our points."
The Rebels are set to line up against former teammates Kurtley Beale and Nick Phipps.
English said he hoped the duo noticed a difference.
"Hopefully we will come out and they won't know what we're doing.
"Hopefully we will paint a different picture and put them on edge; it will be fun to stick it to them."
McGahan said defence was an area he quickly identified that the Rebels could improve.
"We feel that if we can get good improvement there we're going to turn some of those close defeats into victories and that's what we're about."
McGahan said he would give every fit player a run in Albury, with Bryce Hegarty and Angus Roberts sharing the five-eighth duties.
"Most players will play a minimum of 20 and a maximum of 60."
