The Rebels were second on the ladder halfway through last season after winning six of their opening eight games but faded badly for a second straight year to finish 11th.

In 2018 they also started strongly before dropping off in the second half of the campaign to miss the finals.

They've lost Wallabies trio Will Genia, Quade Cooper and Adam Coleman this off-season but managed to retain most of their squad despite a post-World Cup exodus across the competition.

Melbourne kick off their season against the Sunwolves in Japan on Saturday and Haylett-Petty says the earlier start has simplified their approach.

"It's a shorter preseason so for us it's about being really clear and doing a couple of things really well rather than trying to do everything at once," he told AAP.

"Then as the season goes we'll add some variation. The teams who finish better are the teams who end up playing finals and being successful.

"We've come out of the gates really well the past two years which means we've done a lot of things well, just not quite everything."

Toomua emphasised it was about adapting throughout the season and finding new ways to win.

"It's about evolving our game from a winning start and not resting on our laurels," he said.

"You've got to realise when teams are starting to figure you out or if you're playing overseas teams that different styles might work against them.

"Whether it be your kicking game, whether it be your running game, you need to make changes depending on who you're playing."

Toomua believes the adjustments they need to make are tactical and not fitness based.

"Physically guys were in a good place last year. We played a lot of running rugby but probably lost the contact area a little bit against South African teams.

"We've got a plan on how we're trying to attack the year in terms of our game and our style.

"It's making sure we're evolving and constantly getting better throughout the year because it's not how you start it's how you finish."

Australian Associated Press