In front of 44,379 fans at Optus Stadium on Sunday, Matildas captain Kerr scored in the 14th minute for her first international goal since November 2023, and 70th overall.
But the Philippines' damage-control tactics proved too tricky to crack beyond that, with the Matildas not able to add to their tally in a result that could prove costly if positions come down to goal difference.
Although Australia are expected to advance to the quarter-finals with ease, finishing second in their group would lead to a much tougher path to the title.
The Matildas will be back in action on Thursday against Iran on the Gold Coast before rounding out their group stage against South Korea in Sydney next Sunday.
Australia looked their most damaging after Mary Fowler was introduced in the 67th minute, with her creativity causing the Philippines all sorts of problems.
The Matildas finished the match with 85 per cent possession and 15 shots to one.
"It's the big conundrum in football, isn't it?" Matildas coach Joe Montemurro said of his team's inability to finish off their good work.
"We all talk about final third, we all talk about finishing and so on.
"A lot of its instinctive. A lot of it's being a lot smarter in the moment. A lot of it's just having that that bit of coldness in front of the box.
"Can we be better? Yeah, absolutely. But we're getting there.
"We controlled game. Happy to get it out of the way and we move on to the next one."
The world No.15 Australians were forced to thrust fourth-choice goalkeeper Chloe Lincoln into the starting line-up following carnage on the injury front.
Star Lyon custodian Teagan Micah was ruled out of the tournament due to concussion, 2023 World Cup hero Mackenzie Arnold was barely sighted at training this week due to a mystery niggle, while Jada Whyman pulled out of the tournament on Sunday with a knee injury.
The Matildas also went into their tournament opener missing Arsenal midfielder Kyra Cooney-Cross, who has barely played since her mum was diagnosed with incurable cancer in early January.
Lincoln, notching just her fourth Matildas cap, was rarely called into action.
The Matildas enjoyed 87.8 per cent possession in the first half, and whenever the world No.41 Philippines did win the ball back, they more often than not just launched it forward to no one in particular.
Clare Wheeler's floating cross to the back post set up the opening goal, with Caitlin Foord then rising above an opponent to head the ball across goal for Kerr to nod home.
It should have been 2-0 in the 18th minute, only for an unmarked Emily van Egmond to send her close-range header high of the target.
Hayley Raso was celebrating in the 29th minute when she chested down Katrina Gorry's pin-point lob before poking the ball past the advancing goalkeeper.
But VAR correctly determined Raso was marginally offside, resulting in the goal being chalked off.
Philippines coach Mark Torcaso urged his players to be the annoying party poopers in the tournament opener, but instead the visitors only appeared interested in limiting the damage in the first half to ensure their goal difference didn't suffer too much.
It wasn't a surprising tactic, given they were thumped 8-0 when the sides last met in 2023.
The Philippines showed more attacking enterprise in the second half, and the hosts kept pushing for a second goal without much luck.
Fowler, who had played just two matches for Manchester City since recovering from her knee reconstruction, added spark when she was brought on in the 67th minute.
But there were no rewards for Australia, with second-half shots from Clare Wheeler, Gorry and Amy Sayer easily dealt with.
