"Yeah, much better and much easier, because I have the title already. Doesn't matter anymore what is going to happen," Halep told reporters.
"Everything comes now comes as a bonus. So I'll try just to give my best and to see if I'm able to do it again.
"I am too happy to be in this position... it's nothing bad. So I will try to do the things as a kid, enjoying the time. I wanted this badly, and I wanted so much that now having it, I just want to be happy and to smile."
Halep's new outlook on tennis has given rise to questions about her motivation but the 27-year-old is determined not to let them have a negative impact.
"I fought hard and had many tough moments... before lifting that trophy, but I am still motivated because my career doesn't stay in a Grand Slam or ranking," she said.
The world number three beat Tomljanovic in three sets in the pair's only previous meeting -- on the hard courts of Cincinnati last year -- and is aware of the danger the Australian poses.
World number one Naomi Osaka, another player dealing with the burden of expectation, takes on Slovakia's Anna Karolina Schmiedlova on Court Philippe-Chatrier.
Fresh from his victory at the Geneva Open, men's fifth seed Alexander Zverev meets Australian John Millman in the opening match of the day.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Toby Davis)
