Malta had made a bright start to the game at the Centenary Stadium in sweltering conditions, with Haley Bugeja hitting the post and Jackie Burns tipping over an effort from Kailey Willis.
A youthful Northern Ireland side, with Simone Magill and Lauren Wade left on the bench and Kerry Beattie and Casey Howe replacing them in the starting line-up, struggled to get to grips with the game.
That was until a fortuitous own goal from Lipman against the run of play gave the visitors a surprise lead and allowed players to come out of their shell.
“You earn your luck and in the last few games we have put in enough good performances to have one go our way, and I think it settled us and we controlled the game really well second half,” Oxtoby explained.
“I thought the group handled the conditions really it was really hot in the first half but as the sun went down, we were able to wrestle control and we were pretty comfortable.”