The five-eighth will long savour her Test debut after earning player-of-the-match honours in the seven-try shutout.
She produced two try assists and contributed 12 points to the Jillaroos' tally.
"(Jocelyn's) kicking game was amazing, she took her opportunities and we couldn't have asked for more on debut for the Jillaroos in a World Cup," coach Jess Skinner said.
"We're all super proud of her, and we're looking forward to celebrating her over the coming days."
Unbackable favourites leading into the tournament opener, the Jillaroos overcame an ill-disciplined opening 10 minutes to shut out Samoa in the seven-try rout.
Things were far from easy for Australia in the second half, but the damage was already done by halftime, with five-eighth Jocelyn Kelleher and reigning Dally M medallist Tamika Upton leading the way with two try assists apiece.
Samoa, in their first World Cup since 2008, had several chances early but lacked the class to capitalise against their much-fancied opponents.
"The scoreline didn't reflect our effort as a team," Fetu Samoa coach Frank Puletua said.
"There was some good stuff to take out of it. We were lucky enough to debut eight girls, which is good for our nation.
"We're in a good position. We're proud of that as Fetu and for our people."
Gold Coast Titans star Jaime Chapman ended her three-year Jillaroos exodus by scoring Australia's first try in the 11th minute, beating opposite winger Freedom Crichton Ropati out wide.
Australia's greatest ever try scorer, Julia Robinson, lived up to her reputation seven minutes later when she beat three would-be defenders for her 23rd Jillaroos try in 14 appearances.
Tries to back-rower Shaylee Bent and hooker Keeley Nizza followed in quick succession before lock Olivia Kernick crossed moments before halftime to seal a 28-0 lead at the break.
Kernick turned playmaker in the opening five minutes of the second period when she handed the ball off for Keilee Joseph to extend the Jillaroos' lead.
Brave defence would turn the tide for Samoa, who ground their way to more opportunities at the Jillaroos end over the final 25 minutes.
Prop Laikha Clarke went the closest to securing some consolation points for Samoa, but was ruled to have dropped the ball over the line.
Of further concern for Samoa was a suspected knee injury in the dying stages to centre Sarina Masaga.
A try in the final two minutes from Australian centre Jessica Sergis capped the Jillaroos' victory and extended their almost three-year unbeaten run.
"We weren't at our best but it's only the first game together," Jillaroos captain Isabelle Kelly said.
"These learning curves are going to be crucial as we progress through the tournament."
